BFCBrilliance

Articles

The guides behind the tools

Every calculator on this site comes with an article showing how the number is worked out. This is all of them, by category.

250 articles and counting

Tech

Tech

How Far Should You Sit From Your TV?

Two different questions with two different answers — and at 4K they stopped agreeing. At nine feet you can go from a 69-inch screen to a 138-inch one.

Aug 3, 2026 · 4 min read

Tech

Find and Replace Without Regex

Search for 3.14 and you get 3.14 — not 3x14. Every character means itself, which is both what you wanted and the reason it can't hang your browser.

Jul 31, 2026 · 4 min read

Tech

How Long Will My Download Take?

Your 100 Mbps connection moves 12.5 MB/s. If that gap surprises you, it's the reason your downloads look eight times slower than the plan you're paying for.

Jul 31, 2026 · 3 min read

Tech

How to Calculate Aspect Ratio

Learn the decimal, not the colon. 1.7778 against 1.5 tells you which is wider instantly — 16:9 against 3:2 makes you do arithmetic first.

Jul 31, 2026 · 3 min read

Tech

How to Clean Up a Messy List

Trim first — not because of blank lines, but because a deduplicate that runs too early removes almost nothing while looking like it worked.

Jul 31, 2026 · 4 min read

Tech

How to Format and Validate JSON

Formatted and minified at once — and when it's broken, how to translate the parser's error into the character that actually caused it.

Jul 31, 2026 · 3 min read

Tech

How to Write a Good URL Slug

Lowercase, hyphens, and shorter than the title. And never change a published one without a redirect — the slug IS the page's address.

Jul 31, 2026 · 3 min read

Tech

Why Your 1 TB Drive Shows as 931 GB

The drive holds a trillion bytes, exactly as advertised. Windows divides by 1,024³ and prints 'GB' where the standard name is 'GiB'. Nothing is missing.

Jul 31, 2026 · 3 min read

Tech

How to Choose a Strong Password

Length beats complexity, uniqueness beats both, and rotating every 90 days makes things worse. What actually protects an account, and why.

Jul 30, 2026 · 5 min read

Gaming

Gaming

How Drop Rates Actually Work

A 1-in-100 drop is not guaranteed in 100 tries — it's about 63%. The maths behind grinding, and why a long dry streak proves nothing.

Jul 31, 2026 · 4 min read

Finance

Finance

How Much House Can I Afford?

About $268,000 on a $90k income — and your existing debt costs you nothing until it crosses a threshold, then $13,065 of house per $100 a month.

Aug 1, 2026 · 4 min read

Lifestyle

Lifestyle

How to Batch Cocktails

Multiplying the recipe by twelve gives you something harsher than the drink you tested. The missing ingredient is the water that melted off the ice.

Aug 3, 2026 · 4 min read

Lifestyle

How Long to Cook a Roast?

A 4 lb bone-in rib roast is 1h32m to 2h at 325°F. Bone it and roll it and the same joint takes 2h36m — boneless is slower per pound, not faster.

Aug 1, 2026 · 5 min read

Lifestyle

How Long to Cook a Turkey

The 15-minutes-per-pound rule finishes 45 minutes EARLY on an 8 lb bird. It's usually blamed for drying out big ones — the small-bird end is the dangerous one.

Jul 31, 2026 · 4 min read

Health

Health

How Many Sleep Cycles Do I Need?

Five 90-minute cycles is 7h30m. But five real cycles is anywhere from 5h50m to 10h — which is why the 7-hour total is the number worth planning around.

Aug 1, 2026 · 5 min read

Health

How Much Protein Do I Need?

The 0.8 g/kg figure everyone quotes is an RDA — the amount that prevents deficiency. If you train, the published range is roughly double it.

Jul 31, 2026 · 3 min read

Health

How Much Water Should I Drink?

The 8×8 rule is 64 oz. The reference figure is 125 for men and 91 for women — and unlike 8×8, it counts every drink and the water in your food.

Jul 31, 2026 · 3 min read

Health

How to Calculate Your Macros

Fat is 9 calories a gram, not 4 — so a diet that's 25% fat by calories is only 13% fat by weight. And nothing checks that your percentages add to 100.

Jul 31, 2026 · 4 min read

Health

How to Estimate Your One-Rep Max

Two published formulas, side by side — and the thing nobody mentions: they cross at exactly ten reps, which changes how you should read the gap between them.

Jul 31, 2026 · 4 min read

Health

How to Predict Your Race Time

Riegel's formula turns one race into a prediction for another. It's reliable over small jumps — and it quietly assumes you've actually trained for the distance.

Jul 31, 2026 · 4 min read

Health

What Are My Heart Rate Zones?

220 minus age has no research behind it, and it is wrong in opposite directions either side of 40. Here is a better formula, and what easy means in beats.

Jul 31, 2026 · 4 min read

Health

What Does My BMI Actually Mean?

The number is easy to get and easy to over-read. Here's what it measures, what it provably can't, and the more useful figure sitting underneath it.

Jul 31, 2026 · 4 min read

Health

What Is My Ideal Weight?

These formulas were built to dose medication, not to tell you what to weigh — and for a 6'6" man two of them disagree by 12.5 pounds.

Jul 31, 2026 · 4 min read

Health

What Is My Running Pace?

Turn a distance and a finish time into minutes per mile and per kilometre. Then the more useful question: what that average is actually hiding.

Jul 31, 2026 · 4 min read

How-To

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 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 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 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 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 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 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 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 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 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

Gardening

Gardening

Compost Brown to Green Ratio

30:1 and 3:1 are the same rule in different units — carbon to nitrogen by weight, browns to greens by volume. Mixing them up builds a heap that does nothing.

Jul 31, 2026 · 4 min read

Gardening

How Much Sod Do I Need?

Area plus waste, divided by the pallet. But sod is the one material where buying extra is the wrong advice — because it's alive and on a clock.

Jul 31, 2026 · 3 min read

Education

Education

How to Calculate Your GPA

It's not the average of your grades. A one-credit A contributes 4 points; a four-credit B contributes 12 — and that's usually where the gap comes from.

Jul 31, 2026 · 4 min read

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