How-To
How to Calculate Concrete Block Fill
Learn the simple method for estimating grout or concrete fill in a hollow block wall, then use the calculator to get bags and litres.
Aug 16, 2026 · 6 min read
Category
How-To
Step-by-step guides that get you from stuck to done.
42 tools · 46 articles
Free How-To tools
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.
Open the tool →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.
Open the tool →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.
Open the tool →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.
Open the tool →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.
Open the tool →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.
Open the tool →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.
Open the tool →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.
Open the tool →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.
Open the tool →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.
Open the tool →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.
Open the tool →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.
Open the tool →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.
Open the tool →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.
Open the tool →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.
Open the tool →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.
Open the tool →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.
Open the tool →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.
Open the tool →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.
Open the tool →Deck Board Calculator
How many deck boards a deck needs, allowing for the gap between them, plus the screws to fix them down.
Open the tool →Drywall Sheet Calculator
How many sheets of drywall a room needs, from wall and ceiling area, with a waste allowance for cuts.
Open the tool →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.
Open the tool →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.
Open the tool →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.
Open the tool →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.
Open the tool →Hardwood Flooring Calculator
Boxes to buy, with the waste allowance solid hardwood actually needs - and the acclimation step that ruins floors laid without it.
Open the tool →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.
Open the tool →Paver Calculator
How many pavers a patio, path or driveway needs, from the area and the paver size, with an allowance for cuts.
Open the tool →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.
Open the tool →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.
Open the tool →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.
Open the tool →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.
Open the tool →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.
Open the tool →Retaining Wall Block Calculator
Blocks, courses and caps for a segmental retaining wall - including the buried first course that almost every estimate forgets.
Open the tool →Roof Shingle Calculator
Bundles and squares from the FOOTPRINT, not the roof - because the pitch adds area a plan view never shows.
Open the tool →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.
Open the tool →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.
Open the tool →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.
Open the tool →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.
Open the tool →Interior Door Paint Calculator
Estimate paint for interior doors by size, sides, and coats, with quarter-gallon rounding up.
Open the tool →Tile Calculator
How many tiles a floor or wall needs, from the area and the tile size, with a cut-and-breakage allowance.
Open the tool →Paint Calculator
Work out exactly how many gallons of paint your room needs — including doors, windows, and a second coat.
Open the tool →How-To articles
How-To
How Much Does a Load of Lumber Weigh?
A 2×4 is 1.5 by 3.5 inches. Calculate from the name instead of the board and you overstate the weight by 52%.
Aug 3, 2026 · 4 min read
How-To
How Far Can a Deck Joist Span?
A Southern Pine 2×10 at 16" centres spans 14 ft, per AWC DCA 6. The species is worth a foot, and your building department has the final say.
Aug 1, 2026 · 4 min read
How-To
How Many Rolls of Wallpaper Do I Need?
8 rolls for a typical room — but only 6 if the paper had no pattern repeat. The repeat decides how many drops you get from each roll.
Aug 1, 2026 · 4 min read
How-To
How Much Grout Do I Need?
100 sq ft of 12×12 tile at a ⅛" joint takes 4.5 lb. The same 100 sq ft in 2-inch mosaic takes 27 — because grout fills joints, not floors.
Aug 1, 2026 · 4 min read
How-To
How Much Joint Compound Do I Need?
10 gallons per 1,000 sq ft — about a third of a gallon per sheet — and that covers all three coats. Don't multiply it by three.
Aug 1, 2026 · 4 min read
How-To
How Much Paint for Kitchen Cabinets?
A 20-door kitchen is 156 sq ft — 0.89 gallons for two coats. One tin buys the job. The paint was never the expensive part.
Aug 1, 2026 · 5 min read
How-To
How Much Paint to Paint a House?
A typical house is 1,660 sq ft of surface — 9.49 gallons for two coats. The substrate moves that number far more than the brand does.
Aug 1, 2026 · 4 min read
How-To
How Much Sand for Pavers?
One cubic yard covers exactly 324 sq ft at one inch. And one inch is the answer — a thicker sand bed is why patios rut.
Aug 1, 2026 · 4 min read
How-To
How Much Stain for My Deck?
A 16 × 12 deck is 376 sq ft once you count the railing — and 49% of that isn't the floor. Old weathered wood drinks more stain than new wood, not less.
Aug 1, 2026 · 5 min read
How-To
How Much Tile for a Kitchen Backsplash?
21.5 sq ft for a typical kitchen — but you'll buy 30, because tile comes in boxes. Box rounding decides the bill, not the waste percentage.
Aug 1, 2026 · 4 min read
How-To
How Much Underlayment Do I Need?
A 180 sq ft room takes 3 rolls — a roll labelled 100 sq ft really lays about 95. And whatever you do, don't use two layers.
Aug 1, 2026 · 4 min read
How-To
How Many Bags of Concrete Do I Need?
One cubic yard is forty-five 80 lb bags — 3,600 pounds to buy, carry, lift and mix. The weight decides the job, not the bag count.
Jul 31, 2026 · 3 min read
How-To
How Many Blocks for a Retaining Wall?
Blocks per course times courses — plus the buried first course that adds 25% and that most estimates leave out.
Jul 31, 2026 · 3 min read
How-To
How Many Bricks Do I Need?
A brick called 8 inches long measures 7.625 — because 7.625 plus a ⅜ inch joint is exactly 8.0. The name includes the mortar.
Jul 31, 2026 · 4 min read
How-To
How Many Bundles of Shingles Do I Need?
Forget the pitch and a 40 × 30 roof comes out at 40 bundles instead of 45. Measure the ground, not the roof — the slope factor supplies the rest.
Jul 31, 2026 · 4 min read
How-To
How Many Deck Boards Do I Need?
The count comes from the width you're spanning, not the area — and the gap between boards changes it. The arithmetic, and the mistakes it prevents.
Jul 31, 2026 · 4 min read
How-To
How Many Fence Panels and Posts Do I Need?
Take the gates off the run, divide by the panel width, and add one post. The arithmetic, the off-by-one everyone hits, and what to check before digging.
Jul 31, 2026 · 4 min read
How-To
How Many Gallons Is My Pool?
Ten minutes with a tape measure, once — because every chemical dose you'll ever measure is written against this one number.
Jul 31, 2026 · 4 min read
How-To
How Many Pavers Do I Need?
Area divided by the size of one paver, plus waste. The arithmetic, why the pattern matters more than the size, and what the count leaves out.
Jul 31, 2026 · 4 min read
How-To
How Many Sheets of Drywall Do I Need?
Total area divided by sheet area, plus waste. Here's the arithmetic, why you don't subtract doors and windows, and how to pick a sheet size.
Jul 31, 2026 · 4 min read
How-To
How Many Sheets of Plywood Do I Need?
Dividing the area by 32 gives 7. The real layout gives 6 one way and 8 the other — and only one of those directions may be structurally allowed.
Jul 31, 2026 · 4 min read
How-To
How Many Studs Do I Need?
Bays plus one — the off-by-one that leaves you a stud short on every wall. The arithmetic, 16 versus 24 inches, and what the count leaves out.
Jul 31, 2026 · 3 min read
How-To
How Much Baseboard Do I Need?
Perimeter minus doorways, plus waste. But the number that decides how it looks isn't the footage — it's whether each wall runs in one piece.
Jul 31, 2026 · 4 min read
How-To
How Much Carpet Do I Need?
One extra foot of room width can take your waste from 0% to 85% — because carpet comes off a fixed-width roll, and the cost jumps rather than climbs.
Jul 31, 2026 · 3 min read
How-To
How Much Concrete Do I Need for Fence Posts?
Hole minus post — forget the subtraction and you over-order by a seventh. And widening the hole two inches costs far more than it sounds.
Jul 31, 2026 · 3 min read
How-To
How Much Flooring Do I Need?
The waste allowance decides what you shop for. The box size decides what you take home — and those are usually several percent apart.
Jul 31, 2026 · 3 min read
How-To
How Much Gravel Do I Need?
5.9 cubic yards is 8.3 tons. Suppliers are split on which they sell by — and saying the wrong number to the wrong yard is a lorry-sized mistake.
Jul 31, 2026 · 3 min read
How-To
How Much Hardwood Flooring Do I Need?
10–15% waste, not the 5% you'd allow for laminate — and the acclimation step that's behind almost every hardwood floor that fails.
Jul 31, 2026 · 4 min read
How-To
How Much Insulation Do I Need?
R-13 needs 4.06 inches of standard batt. A 2×4 cavity is 3.5. That's a subtraction, not a guideline — and it's why high-density batts exist.
Jul 31, 2026 · 4 min read
How-To
How Much Is a Cord of Wood?
A cord is 128 cubic feet. A "face cord" is a third of that with 16-inch logs, half with 24-inch — the same phrase, sold the same way, for twice the wood.
Jul 31, 2026 · 3 min read
How-To
How Much Paint for a Ceiling?
A 12 × 14 ceiling is 0.96 gallons for two coats — just under one tin. The second coat is where people come up short, not the first.
Jul 31, 2026 · 4 min read
How-To
How Much Primer Do I Need?
Primer covers 200–300 sq ft a gallon where paint covers 350. Buy the same amount as the paint and you're a third of the job short.
Jul 31, 2026 · 4 min read
How-To
How Much Topsoil Do I Need?
Loose soil compacts by 20–25%, so a bed filled level today sits low in a month. Order for the depth you want to end with, not the one you spread.
Jul 31, 2026 · 3 min read
How-To
How to Calculate Board Feet
Thickness × width × length ÷ 12. The part that surprises people is that you're charged for the rough thickness — and that's correct, not a swindle.
Jul 31, 2026 · 4 min read
How-To
How to Calculate Rafter Length
A rafter is a hypotenuse — that part's easy. The part that catches people is that the answer is a line length, not a cut length.
Jul 31, 2026 · 3 min read
How-To
How to Calculate Stair Rise and Run
A 9-foot floor-to-floor needs 14 risers — and 10 feet 10 inches of floor space. The run is what usually forces the redesign, not the rise.
Jul 31, 2026 · 5 min read
How-To
What Size Air Conditioner Do I Need?
20 BTU per square foot — then stop. Rounding up feels like buying safety and actually buys a cold, clammy room.
Jul 31, 2026 · 4 min read
How-To
How Many Tiles Do I Need?
Divide the surface area by the area of one tile, then add for cuts and breakages. Here's the arithmetic, how much waste to allow, and why you buy a spare box.
Jul 30, 2026 · 4 min read
How-To
How Much Concrete Do I Need for a Slab?
Concrete is sold by the cubic yard, so a slab is length times width times thickness. Here's the arithmetic, and why you always order extra.
Jul 30, 2026 · 4 min read
How-To
How to Estimate Paint for Interior Doors
Learn the simple door-paint math: area, sides, coats, and why the calculator rounds up to the nearest quarter gallon.
Jul 30, 2026 · 5 min read
How-To
How Much Paint Do I Need? A Straight Answer
Skip the guesswork at the paint counter. Here's the actual formula, what the can's coverage number really means, and a calculator that does it for you.
Jul 29, 2026 · 5 min read
How-To
How to Get Found in AI Chatbots in 2026
AI chatbots are becoming a real distribution channel. Here’s how to make your content easier to surface without chasing gimmicks.
Jul 27, 2026 · 5 min read
How-To
How to Win on Social Search in 2026
Social platforms are now search engines. Here’s how to make your content show up without chasing every trend or posting more junk.
Jun 25, 2026 · 5 min read
How-To
How to Start a Minecraft Server Your Friends Will Actually Play On
Spinning up a server is the easy part. Keeping people on it is the real skill. Here's the honest playbook from someone who runs one.
Jun 14, 2026 · 3 min read
How-To
How to Start a Blog People Actually Read
Anyone can publish. Getting read is the real skill. Here's the repeatable system for posts that find an audience.
Jun 12, 2026 · 1 min read