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Percentage Calculator
Calculate percentages, percentage change and ratios.
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What is X% of Y?
What is % of ?
X is what percent of Y?
is what % of ?
Percentage change from X to Y
From to
Increase / decrease a number by X%
by %
Percentage formulas
"Per cent" means "per hundred", so every percentage problem is a small rearrangement of the same relationship: part = whole × percent ÷ 100.
- X% of Y:
Y × X ÷ 100. Example: 20% of 150 = 30. - X is what % of Y:
X ÷ Y × 100. Example: 30 is 25% of 120. - Percentage change:
(new − old) ÷ |old| × 100. Going from 80 to 100 is a 25% increase. - Increase / decrease by X%:
Y × (1 ± X ÷ 100). 200 increased by 15% is 230.
Why isn't a 10% rise followed by a 10% fall back to the start?
Because the second percentage is taken of a different base. 100 → 110 (+10%) → 99 (−10% of 110). This is also why percentage change and percentage points are different: a rate moving from 4% to 5% is a 1 percentage-point rise but a 25% increase.