Percentage Calculator
Solve any percentage question in one place.
About Percentage Calculator
Percentage Calculator answers the three percentage questions that come up constantly: 'what is X percent of Y' (15% of 200 is 30), 'X is what percent of Y' (30 is 15% of 200), and 'percent change from X to Y' (200 → 240 is up 20%). Each mode handles one question without making you remember which way the formula goes.
Worked example: enter 18 and 600 in 'percent of' mode and the result is 108. Switch to 'is what percent of' with 108 and 600 and the answer is 18%. In 'percent change' mode, going from 600 to 720 is +20%, and going from 720 back to 600 is −16.67%. That last figure surprises people, but it is correct: percent change is asymmetric — the denominator changes when the starting point changes, so a 20% gain and a 20% loss do not cancel out.
A few practical notes. Percentage point is not the same as percent: an interest rate going from 5% to 6% is a 1 percentage point increase but a 20% relative increase, and the distinction matters when reading economic or business reporting. Also, recovering an original value before a percentage change is its own calculation — if a price after a 20% discount is $80, the original was $80 ÷ 0.8 = $100, not $80 × 1.2 = $96. The 'percent of' mode plus a little algebra handles this; the calculator surfaces it directly when you use 'percent change' in reverse.
All math runs in your browser. Nothing about the numbers you compute is logged or uploaded.