Percentage Calculator
Work out percentages of a number, percentage change, what percent one number is of another, tips, discounts and markups.
The three questions people actually mean
Almost every percentage problem is one of three shapes. What is 15% of 200? — multiply 200 by 0.15 to get 30. 30 is what percent of 240? — divide 30 by 240 and multiply by 100 to get 12.5%. What changed? — subtract the old value from the new one, divide by the old one, and multiply by 100.
Why a 50% drop needs a 100% rise to recover
Percentage change is always measured against the starting number. Fall from 100 to 50 and you have lost 50%. Climbing back to 100 is a rise of 50 on a base of 50 — a 100% gain. This asymmetry is the single most common percentage mistake.
Percent versus percentage point
A rate moving from 4% to 5% has risen by one percentage point, but by 25 percent. Both are correct, and they mean very different things.