Percentage Calculator
Three-in-one percentage calculator: find X% of Y, what % X is of Y, or percent change.
Percentages show up everywhere — discounts, grades, tips, growth rates — but the three most common percentage questions each use a slightly different calculation. This tool covers all three in one place.
The three modes, explained
"What is X% of Y" answers questions like tip or tax amounts. "X is what % of Y" answers questions like test scores. "Percent change from X to Y" answers growth or decline questions, like a price change — and it's the one most people get wrong by hand, since the base of the percentage matters.
Frequently asked questions
Why isn't a 20% decrease reversed by a 20% increase?
Because each percentage is calculated against a different base number — after a 20% decrease, the increase needed to get back to the original is actually 25%, since you're now calculating a percentage of a smaller number.
What's the difference between percentage points and percent?
If a rate moves from 10% to 15%, that's a 5 percentage point increase, but a 50% relative increase — mixing them up is a common source of confusion in news and statistics.