Percentage Calculator
Percent of a number, one number as a percent of another, and percent change.
Your result appears here
Fill in the fields on the left and press Calculate. The answer, the breakdown and a copy button all land in this card.
How it is calculated
A% of B = A ÷ 100 × B; A as % of B = A ÷ B × 100; change = (B − A) ÷ A × 100
Percentage change is always measured against the starting value A, which is why a rise then an equal-looking fall does not return to the start.
Worked example
15% of 200 is 30. Turned around, 30 is 15% of 200. Going from 200 to 230 is a 15% increase, but going from 230 back to 200 is a 13.04% decrease.
Questions people ask
The gain is calculated on the smaller number. 100 falling to 50 then rising 50% only reaches 75 — you need a 100% gain to get back.
A move from 5% to 7% is a rise of 2 percentage points, but a 40% increase. News reports often blur the two.