Three modes: find a percentage of a number, find what percent one number is of another, or calculate percentage change.
Select a mode, enter your two values, and hit Calculate. All math runs in your browser — nothing is sent to a server.
These two are commonly mixed up, but they measure different things. Percentage points describe the raw arithmetic difference between two percentages — going from a 20% interest rate to a 25% rate is a 5-point increase. Percentage change describes the relative movement, calculated against the starting value — that same move is a 25% relative increase (5 ÷ 20 × 100). News headlines about interest rates, tax rates, or survey results sometimes blur this distinction, so it's worth checking which one is being reported.
Percentage change measures relative movement, calculated as the difference divided by the original value. Percentage points measure the raw arithmetic difference. Going from 20% to 25% is a 5-point increase, but a 25% relative increase.
Because percentage change is relative to the starting value, a small absolute change from a tiny base can produce a huge percentage, while the same absolute change from a large base looks small.
Divide the result by the percentage as a decimal to recover the original number — for example, if 20 is 25% of a number, dividing 20 by 0.25 gives 80.