Percentage Calculator
Calculate percentages, percentage changes, and proportions with ease. Free online percentage calculator.
What is a Percentage?
A percentage is a fraction expressed out of 100 — "per cent" is Latin for "per hundred." The notation (
%) was popularized by 17th-century Italian merchants and has since become the universal language for proportions: discounts, taxes, interest rates, exam scores, polling margins, growth rates, and statistical confidence intervals all use it. The four operations you typically need are: percent of a value (15% of $200), reverse percent (30 is what percent of 200?), percent change (80 to 100 is +25%), and percent difference (the symmetric version where order doesn't matter). Each uses a different formula and is easy to mix up. This calculator handles all four with live results. Working with bigger math? Try the Scientific Calculator. Need to apply percentages across a list of items? Use the Cost Calculator.X% of Y
X is ?% of Y
% Change
What is X% of Y?
What isof?
%
Result
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Quick Reference Table
| Percentage | of 100 | of 200 | of 500 | of 1000 |
|---|---|---|---|---|
| 5% | 5 | 10 | 25 | 50 |
| 10% | 10 | 20 | 50 | 100 |
| 15% | 15 | 30 | 75 | 150 |
| 20% | 20 | 40 | 100 | 200 |
| 25% | 25 | 50 | 125 | 250 |
| 33.33% | 33.33 | 66.66 | 166.65 | 333.3 |
| 50% | 50 | 100 | 250 | 500 |
| 75% | 75 | 150 | 375 | 750 |
| 100% | 100 | 200 | 500 | 1000 |
Percentage / Fraction / Decimal
| Percentage | Fraction | Decimal |
|---|---|---|
| 5% | 1/20 | 0.05 |
| 10% | 1/10 | 0.1 |
| 12.5% | 1/8 | 0.125 |
| 20% | 1/5 | 0.2 |
| 25% | 1/4 | 0.25 |
| 33.33% | 1/3 | 0.333... |
| 50% | 1/2 | 0.5 |
| 66.67% | 2/3 | 0.667... |
| 75% | 3/4 | 0.75 |
| 100% | 1/1 | 1.0 |
Quick Formulas
Percentage of a Value(X / 100) * Y
What Percent X is of Y(X / Y) * 100
Percentage Change((New - Old) / |Old|) * 100
How to use this tool
- 1Pick the right operationChoose 'X% of Y' for tips, 'X is what % of Y' for reverse lookup, '% change' for before/after, or '% difference' for symmetric comparison.
- 2Enter your two valuesType the numbers into the input fields. The result updates as you type — no button to press.
- 3Read the result and formulaThe answer appears below with the formula used, so you can verify the math or learn the relationship.