50 articles on percentage math, organized into tutorials, worked examples, comparisons, use cases, and references.
The four percentage formulas in Excel: percentage of a number, percentage change, percent of total, and formatting cells...
The same formulas work in Google Sheets as in Excel, with a few keyboard shortcut and formatting differences.
The percent key on different calculators does different things — here's what to expect on phone, desktop, and four-funct...
A worked example showing three ways to compute 15% of 80, with the mental-math shortcut that makes 15% of anything easy.
20% of 50 is 10. Here's the math and the universal mental shortcut for 20% calculations.
When you have two numbers and want to know what percent one is of the other, divide and multiply by 100.
Three methods to calculate 90% of 50, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 8% of 50, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 75% of 100, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 7% of 200, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 60% of 80, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 6% of 150, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 50% of 100, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 5% of 1000, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 5% of 100, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 45% of 200, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 40% of 200, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 4% of 25, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 35% of 100, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 33% of 90, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 30% of 100, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 3% of 50, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 28% of 70, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 25% of 100, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 22% of 50, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 20% of 200, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 20% of 100, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 2% of 500, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 18% of 75, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 16% of 80, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 15% of 200, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 12% of 60, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 11% of 90, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 10% of 200, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 10% of 100, a mental shortcut, and the real-world contexts where this percentage shows up.
Three methods to calculate 1% of 100, a mental shortcut, and the real-world contexts where this percentage shows up.
Two ways to compare numbers as percentages. One is directional, one is symmetric. Pick the right one for your context.
A 50% markup is not a 50% margin. Here's the math and why confusing them costs businesses real money.
In finance, salary, and business metrics, percentages mean different things depending on whether you mean gross or net v...
Tipping norms vary enormously around the world. What percentage to leave in the US, UK, France, Japan, Australia, and mo...
The standard US 10-point and plus/minus grading scales, plus how to convert percentages to GPA points.
When you can combine a 20% off coupon with a 10% discount, the result is 28% off — not 30%. Here's why and how to think ...
In chemistry, percent yield compares the actual product obtained from a reaction to the theoretical maximum.
The formula for win percentage, ties, and how the major sports leagues handle the math differently.
The formula for percentage increase, with worked examples and common pitfalls including the asymmetry trap.
How to compute percentage decreases with worked examples, plus the trick for applying a decrease in one step.
A basis point is one hundredth of one percentage point. Used in finance to remove ambiguity from interest rate changes.
APR ignores compounding; APY includes it. For a savings account, APY is what you actually earn.
A percentage measures a portion. A percentile measures a rank. They're often confused but mean different things.