Blog
Guides and explainers on calculators, finance, health and more.
August 17, 2026
APY vs APR: Why Your Savings Account and Your Loan Advertise Different Numbers
A 5% APR and a 5% APY aren't the same amount of interest. Here's the compounding math behind the gap, and why banks advertise whichever number flatters them.
August 10, 2026
CAGR vs Average Annual Return: Why They're Not the Same Number
Two investments with an identical 'average' return can have very different actual outcomes. Here's why compounding, not rounding, explains the gap.
August 6, 2026
How Much Is My Business Actually Worth? A Plain-English Guide to Valuation Multiples
Most small business valuations come down to one simple idea: your earnings times a multiple. Here's how that multiple actually gets chosen, and why it matters more than the earnings number itself.
August 4, 2026
When Does Refinancing Your Mortgage Actually Pay Off? (The Break-Even Math That Actually Matters)
A lower rate sounds like an easy yes, but whether refinancing actually pays off comes down to one number: the break-even point. Here's how to find it.
August 3, 2026
How to Actually Estimate What a Road Trip Will Cost in Fuel
Trip fuel cost comes down to three numbers you can usually find in under a minute. Here's how to get a genuinely useful estimate.
July 30, 2026
Why Your Credit Card Balance Never Seems to Get Smaller (Even When You're Paying It Off)
If paying down a credit card feels like it accomplishes almost nothing, the average daily balance method is why. Here's the actual math.
July 27, 2026
Sales Tax, VAT and GST: Same Idea, Different Machinery
They all add a percentage to a purchase price, but sales tax, VAT and GST calculate and collect that tax in genuinely different ways.
July 20, 2026
Why Your Take-Home Pay Is Always Less Than Your Salary (And By How Much)
A $60,000 salary rarely means $5,000 a month in your account. Here's where the difference usually goes.
July 13, 2026
Why Two PDFs With Similar Content Can Have Wildly Different File Sizes
Page count barely affects PDF file size. Here's what actually does, and why compression results vary so much.
July 6, 2026
Why JSON Formatting Matters More Than It Seems
Two JSON files can hold identical data and look nothing alike. Here's why formatting isn't just cosmetic.
June 29, 2026
Why Unit Conversions Sometimes Look 'Off' by a Tiny Amount
1 mile converts to 1.609344 km, not a clean 1.6. Here's why unit conversion often produces long decimals, and why that's expected.
June 22, 2026
What Actually Makes a Password Strong (It's Not Just Length)
Password strength gets reduced to 'use 12+ characters' a lot. Here's what's actually happening under that advice.
June 15, 2026
GST: Adding vs Removing Tax From a Price, Explained
Adding GST to a price and removing GST from a price use two different formulas, not just one in reverse. Here's why.
June 8, 2026
BMI vs BMR: What's the Difference and Why It Matters
Two acronyms, two very different numbers. Here's how BMI and BMR relate, and when each one is actually useful.
June 1, 2026
How EMI Is Calculated (And Why Your Monthly Payment Looks the Way It Does)
EMI feels like a black box until you see the formula. Here's what's actually happening behind that monthly number.