Tools
Free tools that actually do the job
Calculators and planners you can use right now — no signup, no download, no watching an ad first. Each one pairs with a guide that explains the maths behind it.
229 tools and counting
Tech
Read the guidesThe tools, gadgets, AI, and software shaping how we live and work.
DNS Propagation Time Calculator
Estimate how long DNS changes may take to fully reach users worldwide.
Battery Life Calculator
Runtime from capacity and draw - and why a 10,000 mAh power bank only delivers about 6,660 mAh at the USB port.
Cloud Storage Cost Calculator
Storage is the cheap part. Compare a standard tier against an archive one once retrieval and egress are counted, and find the crossover.
Colour Contrast Ratio Calculator
The WCAG contrast ratio for any two colours, checked against all four thresholds - plus whether plain black or white text would do better.
Monthly Data Usage Calculator
Where your gigabytes actually go - and why the video quality setting matters more than everything else on the list combined.
Password Entropy Calculator
Entropy in bits, and how long a password survives a given attack - as long as it was chosen randomly, which is the assumption doing all the work.
Memory Card Capacity Calculator
How many photos fit on a card - and why half an hour of 4K video costs you more of it than eight hundred RAW frames.
Print Size and DPI Calculator
How big you can print an image before it softens - and why 300 dpi is only the right answer for something held in your hands.
PSU Wattage Calculator
What power supply a build needs - sized for transient spikes rather than the sum, and for the load where a PSU is actually most efficient.
RAID Rebuild Time Calculator
How long a replacement drive takes to rebuild, how much data must be read to do it, and what the drive's own error spec says about the odds.
RAID Usable Capacity Calculator
How much of your array you actually get to use, what the OS will report instead, and the cost of every terabyte that survives.
TV Viewing Distance Calculator
How far to sit, from the published viewing-angle standards - and the separate distance at which you would stop seeing pixels.
Uptime SLA Downtime Calculator
What each 'nine' actually costs you in minutes - and why 99.99% is a different engineering problem rather than a slightly better one.
Video Bitrate Calculator
The bitrate that hits a target file size - with the audio track subtracted, because it comes out of the same budget and people forget it.
Aspect Ratio Calculator
Resize without distorting: give the original dimensions and one new one, get the other back. Plus the ratio as a decimal, which is the number worth learning.
Case Converter
Paste text once and get UPPERCASE, lowercase, Title Case and Sentence case together - no mode to pick, nothing sent anywhere.
Download Time Calculator
How long a file takes at your connection speed - including the conversion nearly everyone gets wrong, because megabits and megabytes differ by eight.
File Size Converter (GB to MB)
Both answers, side by side. A 1 TB drive really does hold a trillion bytes - and Windows really does call that 931 GB. Neither is lying.
Find and Replace (Online)
Literal find and replace - deliberately not regex, so a pattern can never hang your browser and what you type means itself.
JSON Formatter & Validator
Paste JSON and get it indented and minified at once - and if it is broken, the parser's own error with the line and column.
Line Sorter & Deduplicator
Sort and de-duplicate a list - with the cleaned version shown too, because raw de-duplication misses "apple" and "apple " and always will.
PPI & Screen Size Calculator
Pixel density from a screen's diagonal and resolution, plus its real width and height - because a bigger 4K panel can be less sharp than a smaller 1440p one.
URL Slug Generator
Turns a headline into a clean URL slug - and shows you the shortened version too, because the best slug is usually not the whole title.
Text Cleaner
Trim every line, drop the blanks, remove duplicates - all four results at once, in your browser, on lists that have been through three programs.
URL Encoder & Decoder
Both directions at once, so you never pick the wrong one - and it encodes the component-safe way, which is the one you almost always want.
Base64 Encoder & Decoder
Paste text or Base64 and get both forms at once. Runs entirely in your browser — nothing is uploaded.
Password Generator
Strong random passwords generated in your browser, at four lengths. Nothing is sent anywhere and nothing is stored.
Gaming
Read the guidesMinecraft, servers, and the games worth your time — tips, builds, and what's worth playing.
Raid Lockout Calculator
See how many weekly lockouts you need for a 50% or 90% chance of at least one drop.
Battle Pass Completion Calculator
Will you finish before the season ends? Weeklies do not scale with days left, which is why the answer is rarely what a simple average suggests.
Crit Chance vs Crit Damage Calculator
Which stat gives more damage for the next point you spend - and the exact crit damage figure where the answer flips.
Damage Reduction Stacking Calculator
Reductions multiply, they do not add - 30% and 20% and 15% is 52.4%, not 65%. Combine your sources into the one figure that matters.
FPS to Frame Time Calculator
The same +30 fps is worth ten times more at 30 than at 120. Frame time is the unit that makes upgrades comparable.
Gear Upgrade Cost Efficiency Calculator
Score any upgrade as cost per 1% damage - the one number that lets you compare a cheap trinket against an expensive weapon fairly.
Loot Table Expected Value Calculator
What a run is really worth per hour - and how much of that value sits in a drop you might farm for a day without seeing.
Minecraft Brewing Ingredient Calculator
One ingredient brews three potions, so a stack of nether wart goes far further than people think. Work out the shopping list and the time before you start.
Minecraft Farm Rate Calculator
Time your farm for a real items-per-hour figure, how long it takes to fill a double chest, and whether you measured long enough to believe it.
Redstone Timing Calculator
Repeater delays into real seconds - and back again, so you can build the delay you actually want instead of guessing at repeaters.
Nether Travel Time Calculator
One block in the Nether is eight in the Overworld - but portal overhead means short trips are still faster on the surface.
Sensitivity for a Target cm/360
You know the cm/360 you want. This gives the in-game sensitivity that produces it - or the DPI to change instead if you would rather keep your sens.
Speedrun Pace Calculator
Ahead or behind at a split, and what the run finishes in - worked two ways, because the two honest projections disagree most when you most want an answer.
Tournament Bracket Calculator
Bracket size, byes, rounds and match count from your entry list - and why a single-elimination event always runs one match short of its entrants.
XP Boost Worth-It Calculator
A boost is only worth what it earns minus what getting it cost you. The break-even is simply the boost percentage times its duration.
Minecraft Anvil Cost Calculator
The prior work penalty doubles every time — 0, 1, 3, 7, 15, 31, 63. That is why the sixth use says Too Expensive, and why combining order matters so much.
Mouse Sensitivity Converter (cm/360)
The same eDPI means different things in different games — 800 eDPI is 51.95 cm/360 in CS2 and 16.33 in Valorant. Only cm/360 compares across titles.
DPS Calculator
Damage per second with crit chance and crit damage folded in, plus how long a target actually takes to kill - generic maths, your game's numbers.
Drop Chance Calculator
Your real odds of getting a drop over many attempts, and how many tries it takes to be reasonably sure. Works for any game.
eDPI Calculator
DPI times in-game sensitivity. It's the only number that compares two players' aim - and the one that tells you what sens to use after changing DPI.
Effective Health (EHP) Calculator
What your health bar is really worth once damage reduction is counted - and why the same 10% of resistance is worth fifteen times more at 80% than at 40%.
Gacha Pity & Pull Cost Calculator
What it costs to guarantee the pull using your game's pity cap - and why the worst case for a featured item is double the number most people budget for.
Minecraft Beacon Calculator
164 blocks for a full pyramid - and the fourth tier alone is 81 of them, half the total, for one extra effect.
Minecraft Fuel Calculator
How much fuel a smelt actually needs - and the reason nine coal in a crafting grid smelts eight more items than nine coal in a furnace.
Nether Portal Coordinate Calculator
Convert Minecraft coordinates between the Overworld and the Nether, both directions at once, so your portals link where you want them.
OSRS XP to Level Calculator
The gap to your target and what it costs in hours - built around the fact that level 92 is exactly half the XP of 99.
Minecraft XP to Level Calculator
Find how much XP you need to reach a target Minecraft level, or how many levels your XP gives you.
Finance
Read the guidesMoney, investing, side hustles, and building wealth — explained simply.
Invoice Factoring Fee Calculator
Estimate how much cash you get from a factored invoice and the total fee in dollars.
Freelance Hourly Rate Calculator
Your rate is not your old salary divided by 2,080. On typical assumptions it is nearly three times that - and here is where every multiple comes from.
Inflation Adjusted Value Calculator
At 3%, money loses half its purchasing power in about 23 years - inside a single working life, without anything dramatic happening.
Invoice Late Fee Calculator
What an overdue invoice has actually accrued - and why '1.5% a month' is 18% a year, or 19.6% once it compounds.
Lease vs Buy Car Calculator
Compared over the same period, the two are usually much closer than they look - and the whole answer hinges on a resale value nobody knows.
Overtime Pay Calculator
Time-and-a-half on a fifth of your hours raises your effective rate by only 8%. The premium is smaller than it sounds.
Take-Home Pay Calculator
The order deductions come off decides what you keep - and a $500 pre-tax contribution only costs $390 of take-home.
Profit Margin vs Markup Calculator
A 50% markup is a 33% margin. Confusing the two is the most expensive arithmetic mistake in small business pricing.
Refinance Break-Even Calculator
How many months to recoup the closing costs - and whether a lower payment is actually costing you more over the life of the loan.
ROI and Payback Period Calculator
Payback ignores everything after it pays back. ROI ignores when the money arrives. You need both, and they disagree.
Side Hustle Hourly Profit Calculator
Revenue over hours is the flattering number. Once fees, costs, tax and unpaid time are in, it can land below minimum wage.
Debt Snowball vs Avalanche Calculator
Avalanche saves $866 on these numbers. Snowball clears your first debt 21 months sooner. That is the whole trade-off, in two figures.
Mortgage Affordability Calculator
The 28/36 rule is a lender convention, not a law — and existing debt costs you nothing until it crosses the threshold, then $13,065 of house per $100 a month.
Rent vs Buy Calculator
On realistic numbers the two land within a few thousand dollars over seven years — and the whole margin is an appreciation rate nobody can predict.
Break-Even Calculator
How many units you need to sell to cover your fixed costs - and why the contribution margin, not the price, is the number that decides it.
Car Loan Calculator
Your monthly payment, and the number the dealer will not lead with - what the car costs in total once the interest is counted.
Compound Interest Calculator
What a lump sum grows to, and the same money at simple interest beside it - because the gap between those two numbers is the whole idea.
Credit Card Payoff Calculator
How long a balance takes to clear at a fixed monthly payment, what it costs in interest, and how much of this month's payment never touches the balance.
Discount Calculator
What you actually pay after a discount - including stacked ones, which never add up to what they look like. 30% then 20% off is 44% off, not 50%.
Emergency Fund Calculator
How much you actually need set aside, based on what your months genuinely cost rather than a percentage of your income - and how long it takes to get there.
Hourly to Salary Calculator
What an hourly rate comes to over a year once unpaid time off and overtime are counted - not the hourly rate times 2,080.
Loan Payoff Calculator
How long a balance takes at a given payment - and the point below which it never clears at all, which is the number worth seeing first.
Mortgage Payment Calculator
The monthly payment, and the total interest beside it - because on a 30-year loan the interest is usually larger than you expect.
Retirement Savings Calculator
What regular contributions grow into - and the split between what you paid in and what the growth added, which is the number that argues for starting early.
Sales Tax Calculator
Both directions. Working backwards from a total is the one people get wrong — you divide by 1.08, you don't multiply by 0.92.
Savings Goal Calculator
Work out what you need to put aside each month to hit a savings goal by a date, with the interest your balance earns along the way doing part of the work.
Tip Calculator
Tip, total and the per-person split - plus the rounded-up figure, because the number you actually want is usually a whole one.
Lifestyle
Read the guidesHabits, productivity, travel, and living well day to day.
Paint Drying Time Calculator
Estimate paint drying times with Sherwin-Williams guidance for dry-to-touch, recoating, and full cure.
Appliance Running Cost Calculator
What one appliance actually costs to run per year, from its wattage and your own electricity rate - including what it costs while switched off.
Baker's Percentage Calculator
Turn baker's percentages into real weights - and get the hydration right when a sourdough starter brings its own flour and water.
Cocktail Batch Scaler
Scale one drink to a batch and add back the water the ice would have given you - the step that makes batched cocktails taste flat without it.
Flight Time & Layover Calculator
Enter your two flight times and see how much slack the connection really has - and how late the inbound can be before you miss it.
Cost Per Serving Calculator
What a serving really costs once trim, peel and bone come out - and how much of a bulk pack you have to actually use for it to be cheaper.
Heat Index Calculator
What the air actually feels like, using the National Weather Service equation - plus the 15°F that full sun adds and the number leaves out.
Laundry Detergent Cost Calculator
What a wash actually costs, and what habitually filling the cap instead of measuring adds up to over a year.
Meal Prep Portion Calculator
How many portions a week of meal prep actually is, how much RAW food that means, and how many portions have to go in the freezer.
Luggage Weight Calculator
Add up what you are packing against your own allowance - including the empty suitcase, which can be a sixth of it before you put anything in.
Pet Food Portion Calculator
Split the daily amount from your food's own feeding guide into meals, take the treats out of it rather than adding them on top, and see how long a bag lasts.
Pizza Dough Calculator
Scale a dough ball you already like to any other size. Dough follows AREA, so 12 to 16 inches is 1.78x the dough, not 1.33x.
Temperature Converter
Celsius, Fahrenheit, Kelvin and oven gas mark at once - with the gas mark left blank rather than guessed below mark 1.
Time Zone Meeting Planner
Find the hours two people in different time zones can actually both make - including the overlap that only exists on their next day.
Volume & Capacity Converter
Millilitres to gallons in one step, with US and Imperial kept apart - because a US pint and a UK pint are 20% different.
Event Catering Quantity Calculator
Turn a guest count into portions, drinks and bottles - including the glasses-per-bottle arithmetic that decides whether the bar runs dry.
Weight & Mass Converter
Enter a weight in any unit and see it in all eight at once, using the exact 1959 definitions rather than rounded factors.
Moving Box Calculator
Published box counts vary threefold, so treat the count as a range. What is not a guess: at 25 lb per cu ft, a box of books must stay under 2 cu ft.
Party Food & Drink Calculator
Six ounces on the plate is eight ounces at the shop. Cooking loss and offering a second main dish are the two things that quietly break a catering estimate.
Roast Cooking Time Calculator
Boning and rolling a rib roast makes it take LONGER per pound, not shorter — 39-43 min/lb against 23-30. Time is the plan; the thermometer is the answer.
Coffee to Water Ratio Calculator
How much coffee for the water you are actually brewing, at any strength - in grams, because a scoop is why it tastes different every morning.
Cups to Grams Converter
A cup of flour is 120 g and a cup of honey is 336 g. There is no single conversion - the ingredient IS the conversion.
Length & Distance Converter
Enter a length in any unit and see it in all eight at once - millimetres to miles, with the exact conversions rather than rounded ones.
Recipe Scaler
Scale a recipe up or down and get the awkward amounts back as spoons you can actually measure, instead of 1.125 cups.
Road Trip Gas Cost Calculator
What the fuel for a trip actually costs, split between everyone in the car - and what each mile is costing you before anything else is counted.
Turkey Cooking Time Calculator
The USDA chart, not a flat minutes-per-pound rule - which under-cooks a small bird and over-cooks a 24 lb one by a full hour.
Vacation Budget Calculator
What a trip actually costs once nights, days and people are counted separately - because a seven-night holiday has eight days of eating.
Health
Read the guidesFitness, nutrition, and wellbeing backed by what works.
Dehydration Risk Session Planner
Estimate how much body weight you could lose in a session and whether it passes the 2% dehydration threshold.
Blood Pressure Category Calculator
Where a reading falls on the American Heart Association's categories - and which of your two numbers is the one deciding it.
Body Surface Area Calculator
Mosteller and Du Bois side by side, because they disagree - and the gap is the reason this is a clinician's number rather than yours.
Cycling Power to Weight Calculator
Watts per kilo, the climbing speed it implies, and what a kilo off the bike is actually worth in seconds.
Daily Sodium Intake Calculator
Sodium and salt are not the same number - 5 g of salt is 2,000 mg of sodium. Confusing them is a two-and-a-half-fold error.
Daily Fibre Intake Calculator
The 25 g and 38 g figures are not about being a woman or a man - they are 14 g per 1,000 calories at two assumed appetites.
Sweat Rate and Hydration Calculator
Weigh yourself before and after a session to find your real sweat rate - which is the CEILING on what to drink, not a target to hit.
Sleep Debt Calculator
Add up a week honestly. The arithmetic is easy - it is the idea that a weekend lie-in repays it that does not survive contact with the evidence.
Critical Swim Speed Calculator
Your threshold pace from a 400 and a 200 time trial - and why it is slower than your 400 pace, which is the point people get wrong.
Training Load Ratio Calculator
How this week compares with your recent average - worked both ways, so you can see the mathematical coupling the popular version hides.
VO2 Max Estimator (Cooper Test)
Run as far as you can in 12 minutes. One subtraction, one division - and about ten percent of error, which the tool reports as a range.
Waist to Height Ratio Calculator
Keep your waist to less than half your height. The ratio, the bands, and the actual waist measurement each band means for you.
Walking Calorie Calculator
The figure your tracker shows includes what you would have burned sitting down. The walk itself added considerably less.
Sleep Cycle Calculator
Five cycles is 7h30m at the average — but anywhere from 5h50m to 10h once you use the real 70-120 minute range. The 7-hour floor is the sturdier number.
BMI Calculator
Your BMI in either unit system, and the weight range it corresponds to for your height - plus an honest account of what the number cannot tell you.
Body Fat Calculator (Navy Method)
The Hodgdon-Beckett circumference formula, in INCHES - which matters, because feeding the same constants centimetres reports 26.7% for a body that is 20.1%.
Calorie Deficit Timeline Calculator
How long a given deficit takes - built on the 3,500-calorie rule, which researchers have shown overestimates real weight loss. The tool says so.
Heart Rate Zone Calculator
Training zones from the Tanaka formula rather than 220 minus age, using your resting heart rate - so 'easy' comes out as a number you can actually hold.
Ideal Weight Calculator (Devine & Hamwi)
Two published formulas, side by side, disagreeing by pounds - and both were built to dose medication rather than to tell you what to weigh.
Macro Split Calculator
Percentages into grams - and a check that your three add to 100, which is where most macro plans quietly fail.
One-Rep Max Calculator
Estimate your 1RM from a set you actually did, using both Epley and Brzycki side by side - two published formulas that cross at exactly ten reps.
Protein Intake Calculator
The 0.8 g/kg RDA is a minimum to avoid deficiency, not a target. If you train, the published range is roughly double it.
Race Time Predictor
Predict a race time from one you have already run, using Riegel's formula - and see how much your pace is expected to slow over the longer distance.
Running Pace Calculator
Turn a distance and a finish time into your pace per mile and per kilometre, with the speed in both units - the numbers you need to pace the next one.
Steps to Miles Calculator
Converts steps using YOUR height rather than the '2,000 steps per mile' rule - which quietly describes someone 6 ft 4 in tall.
TDEE Calculator
What your body burns in a day, using the Mifflin-St Jeor equation - split into the part that is just staying alive and the part your activity adds.
Daily Water Intake Calculator
The 8x8 rule is 64 oz. The actual reference figure is 125 oz for men and 91 for women - and unlike 8x8, it counts food and every other drink.
How-To
Read the guidesStep-by-step guides that get you from stuck to done.
Concrete Block Fill Calculator
Work out how many litres of grout or concrete fill a hollow block wall will need, plus how many bags to buy.
Lumber Weight Calculator
What a load actually weighs - using the REAL dimensions, because a 2x4 is 1.5 by 3.5 and nominal figures overstate weight by half.
Backsplash Tile Calculator
A backsplash is a small job measured in a strange shape — 18 inches tall. Box rounding, not the waste percentage, decides what you actually buy.
Kitchen Cabinet Paint Calculator
A 20-door kitchen is about 156 sq ft — under a gallon for two coats. The paint is never the expensive part of this job.
Deck Joist Span Calculator
Looks up the AWC DCA 6 prescriptive span table — a Southern Pine 2x10 at 16 in centres spans 14 ft. Your local building department has the final say.
Deck Stain Calculator
The floor is the easy half. Railings and steps are nearly 49% of a typical deck — and old, weathered wood drinks more stain than new wood, not less.
Exterior Paint Calculator
Perimeter times wall height, plus the gables everyone forgets. A typical house is 9.49 gallons for two coats, and the substrate moves that more than the brand.
Grout Calculator
Grout is driven by tile SIZE, not floor size. Small tiles have far more joint per square foot — a 2-inch mosaic needs six times the grout of a 12-inch tile.
Joint Compound Calculator
USG's own submittal sheets say 9.4-10 gallons per 1,000 sq ft of panel — about a third of a gallon per sheet, for the whole three-coat finish.
Paver Sand Calculator
One cubic yard covers exactly 324 sq ft at one inch — and one inch is the whole answer. A thicker sand bed is the commonest reason a patio ruts.
Underlayment Calculator
Rolls are sold by nominal area, but overlaps and trimming eat into it. And doubling underlayment up does not help — it makes the floor worse.
Wallpaper Roll Calculator
Rolls are bought in whole drops, and the pattern repeat decides how many drops you get from one. A 21-inch repeat can cost you two extra rolls.
Air Conditioner BTU Calculator
20 BTU per square foot, plus the ENERGY STAR adjustments - and a warning about the mistake everyone makes, which is buying too big.
Baseboard & Trim Calculator
How much baseboard a room needs once doorways are taken out, with an allowance for mitre cuts and the lengths you can actually buy.
Board Foot Calculator
Board feet and cost for hardwood, using the ROUGH thickness the yard prices from - which is not the thickness you take home, and that is correct.
Brick Calculator
Bricks per square foot worked from your actual brick and joint, not a rule of thumb - because the joint width moves the count by a seventh.
Carpet Calculator
Carpet comes in fixed roll widths, so one extra foot of room can double what you buy - and turning the room 90 degrees often costs less.
Ceiling Paint Calculator
A 12 x 14 ceiling is under a gallon for two coats. The number that catches people is the SECOND coat, not the first.
Concrete Bag Calculator
Bags for a small pour - and the point where bags stop being sensible, which is around 45 of them and two tons of lifting.
Deck Board Calculator
How many deck boards a deck needs, allowing for the gap between them, plus the screws to fix them down.
Drywall Sheet Calculator
How many sheets of drywall a room needs, from wall and ceiling area, with a waste allowance for cuts.
Fence Panel & Post Calculator
How many fence panels and posts a run needs, allowing for gates, plus the rails and the concrete holes to dig.
Firewood Cord Calculator
A cord is 128 cubic feet. A "face cord" of 16-inch logs is exactly a third of that - so the same word can mean three times the wood.
Flooring Calculator
How many boxes of laminate or vinyl plank a room needs - and why the box size, not the waste allowance, decides what you actually buy.
Gravel Calculator
Cubic yards AND tons, because suppliers quote one or the other - and ordering the right number in the wrong unit is a lorry-sized mistake.
Hardwood Flooring Calculator
Boxes to buy, with the waste allowance solid hardwood actually needs - and the acclimation step that ruins floors laid without it.
Insulation R-Value Calculator
How many inches your target R needs - and whether it fits. A 2x4 cavity is 3.5 in, and standard batt can't reach R-13 in it.
Paver Calculator
How many pavers a patio, path or driveway needs, from the area and the paver size, with an allowance for cuts.
Plywood Sheet Calculator
How many sheets you actually need - counted by LAYOUT rather than area, because which way you run them can change the answer by two whole sheets.
Pool Volume Calculator
How many gallons your pool holds, from its shape and both depths - the number every chemical dose on every label is written against.
Post Hole Concrete Calculator
Bags of concrete for fence posts, with the post's own volume subtracted - forget that and you over-order by about a seventh.
Primer Calculator
Primer covers 200-300 sq ft a gallon where paint covers 350 - so the same wall needs about 40% more primer than you'd assume.
Rafter Length Calculator
Rafter length from your span and roof pitch, including the overhang - plus the ridge deduction that catches people who measure to the peak.
Retaining Wall Block Calculator
Blocks, courses and caps for a segmental retaining wall - including the buried first course that almost every estimate forgets.
Roof Shingle Calculator
Bundles and squares from the FOOTPRINT, not the roof - because the pitch adds area a plan view never shows.
Stair Rise & Run Calculator
Riser height, tread count and the total run - including the floor space a staircase actually eats, which is usually the surprise.
Topsoil Calculator
Cubic yards and tons - plus the settling allowance, because topsoil delivered loose loses roughly a fifth of its depth once it beds in.
Wall Stud Calculator
How many studs a wall needs at 16 or 24 inch spacing, plus the plate timber — with the off-by-one people always miss.
Concrete Slab Calculator
Cubic yards of concrete for a slab, from its length, width and thickness, with a waste allowance so you do not come up short.
Interior Door Paint Calculator
Estimate paint for interior doors by size, sides, and coats, with quarter-gallon rounding up.
Tile Calculator
How many tiles a floor or wall needs, from the area and the tile size, with a cut-and-breakage allowance.
Paint Calculator
Work out exactly how many gallons of paint your room needs — including doors, windows, and a second coat.
Gardening
Read the guidesBeds, lawns, and what to plant when — working out what a garden actually needs.
Cover Crop Seed Calculator
Turn your seed bag's own rate into the amount for your beds, with the broadcasting increase and the bags you actually have to buy.
Drip Irrigation Zone Calculator
How many emitters your supply can actually run at once - measured with a bucket and a stopwatch, not assumed from a table.
Firewood Drying Time Calculator
When your wood is ready to burn - on the EPA's seasoning baseline of six months for softwood and a year for hardwood, with the moisture meter as the real test.
Growing Season Fit Calculator
Does the crop actually fit your season? Enter your frost-free days and its days to maturity, and see the slack - or how short you are.
Crop Rotation Planner
Work out which bed a crop family moves to in any future year, and whether your number of beds actually gives the rest interval you need.
Lime Rate Calculator
Convert your soil test's lime recommendation into bags of the product you actually bought - adjusted for its CCE, and split if the rate is too high for one go.
Greenhouse Heater Size Calculator
Heat loss from your glazing's own U-value and your own design low - the two numbers that decide heater size, and neither of them is guessable.
Hydroponic Nutrient Mixing Calculator
Scale your bottle's own dose rate to your reservoir and your top-ups - including the ml/gal against ml/L conversion that is a factor of 3.79.
Mushroom Substrate Calculator
Water to add for your target moisture, and spawn to match - worked from dry weight, which is the only figure that stays put.
Pond Liner Size Calculator
Liner size from your pond's dimensions - remembering that the depth is added twice, once going down each side, plus the overlap you bury.
Potting Mix Ratio Calculator
Turn a parts recipe into real volumes for a batch of pots - and buy in DRY quarts, which are 16% bigger than the liquid ones.
Rain Barrel Capacity Calculator
How much water a roof actually sheds per inch of rain, how little of it one barrel holds, and how many you would need to catch the lot.
Seed Starting Date Calculator
Work the indoor timeline backwards from your own last frost date - sowing, emergence, hardening off and planting out, all in days you can count on a calendar.
Sprinkler Coverage Test Calculator
Run a catch test with five tins and get two numbers: your sprinkler's real output rate, and how evenly it actually covers the ground.
Tree Spacing Calculator
Space trees on their MATURE spread, not the size in the pot - and keep them off the house by half a canopy plus clearance.
How Many Plants to Grow Calculator
Work back from how much you actually eat to how many plants to sow - with a loss allowance, because not every plant makes it.
Compost Brown-to-Green Ratio Calculator
The famous 30:1 is carbon to nitrogen BY WEIGHT. What you actually measure is roughly 3:1 browns to greens BY VOLUME — two different numbers for one rule.
Garden Edging Calculator
Linear feet, pieces and stakes for a bed border - including the bit people forget, which is that a bed against a wall does not need edging all the way round.
Grass Seed Calculator
Seed is sold by weight but applied by rate, and the rate belongs to the grass - bluegrass goes down at a quarter of the fescue weight, and twice the seeds.
Lawn Fertilizer Calculator
You apply pounds of NITROGEN, not pounds of fertilizer. A 16-4-8 bag needs 6.25 lb to deliver 1 lb of N - and that ratio is the whole calculation.
Plant Spacing Calculator
How many plants fit a bed at your chosen spacing, laid out in rows — so you buy the right number instead of guessing.
Raised Bed Material Calculator
Boards for a raised garden bed - and the height it will really end up, which is taller than the one you asked for and needs more soil than you planned.
Raised Bed Soil Calculator
How much soil a raised bed needs, in cubic feet, cubic yards and bags — for one bed or a whole plot.
Sod Calculator
How much sod your lawn needs and how many pallets that is - plus the constraint no other material has, which is that it is alive and on a clock.
Lawn & Garden Watering Calculator
An inch of water over 1,000 sq ft is 623 gallons. Work out how long your sprinkler needs — and measure its real output with a tuna can.
Mulch Calculator
Work out how much mulch a bed needs in cubic yards and bags, from its size and how deep you want to go.
Education
Read the guidesGrades, study plans, and the maths of getting through a course.
Class Attendance Calculator
How many sessions you can still miss and stay above the attendance rule — and how many you have already spent.
Class Rank Percentile Calculator
Turn a class rank into a percentile — and see why the two common formulas disagree with each other.
Degree Progress Calculator
How much of your degree is actually done — by credits, not by years elapsed, which is the number that misleads.
Essay Word Count Planner
How many words each section of an essay should get, and how many sources and paragraphs that implies.
Exam Curve Calculator
What your raw mark becomes under the four curves instructors actually use — they disagree with each other by a lot.
Exam Time Per Question Planner
Minutes per question weighted by marks, with reading and checking time taken out first.
Flashcard Daily Load Calculator
New cards a day to finish a deck on time — and the review load that comes with them, which is the part that breaks.
Group Project Workload Splitter
Hours per person on a group project once the shared work everyone forgets to count is included.
Minimum Passing Score Calculator
The lowest mark on what's left that still gets you over the line — and whether the line is still reachable at all.
Pages to Words Converter
Convert a page requirement into a word count, using the double-spaced convention markers actually assume.
Presentation Timing Calculator
How long a talk really runs from its script and slides — and how much you have to cut to fit the slot.
Pages Per Day Calculator
Pages a day to finish a book by a deadline — with and without the days you will realistically miss.
Semester Credit Hour Calculator
How many credits a semester you need to finish on time — and what one skipped term costs you.
Study Session Spacing Planner
How many study sessions fit before your exam, how far apart, and what one lost week costs.
Target GPA Calculator
The GPA you need across your remaining credits to reach a cumulative target — and whether it is still reachable.
Tuition Cost Per Credit Calculator
What a single course really costs once fees are included — and what dropping one costs you on top.
Typing Speed WPM Calculator
Gross and net words per minute from a timed passage — using the five-character word every typing test uses.
Weekly Study Hours Calculator
The hours a week a credit load really implies, as a range — and whether it fits alongside a job.
Study Time to Grade Goal Calculator
Estimate how many study hours you need to raise a course grade by a target amount.
Final Grade Calculator
What you need to score on the final to hit the grade you want — and the best and worst you can still finish with.
GPA Calculator
Weighted by credit hours, which is the whole point - a one-credit A moves your GPA far less than a four-credit B does.
Reading Time Calculator
How long a book will actually take - built on a 190-study meta-analysis whose real figure is lower than the number everyone quotes.
Study Time Planner
How many hours the material actually needs, and whether they fit in the days you have left — which is the answer people wish they'd got in week two.
Test Score Calculator
Turn points into a percentage and a letter grade, and see exactly how many more points would have moved you up a grade.
Weighted Grade Calculator
Work out your course grade when categories carry different weights - and see how much ten points on the final would actually move it.
Word & Character Counter
Paste anything and get the word, character and line counts at once. Runs in your browser — nothing is uploaded.