Percentage Calculator
Find any percentage, common percentage phrases, percentage difference, and percentage increase/decrease — all in one tool.
Percentage Calculator
Please provide any two values below and click "Calculate" to get the third value.
Percentage Calculator in Common Phrases
Percentage Difference Calculator
Percentage Change Calculator
Please provide any two values below and click "Calculate" to get the third value.
Understanding Percentages
A percentage is a way of expressing a number as a fraction of 100. "P% of X" means (P ÷ 100) × X. For example, 25% of 80 is (25 ÷ 100) × 80 = 20. Percentages are used everywhere — discounts, interest rates, statistics, and grades — because they make it easy to compare proportions on a common scale.
To increase a value by P%, multiply it by (1 + P/100). To decrease a value by P%, multiply it by (1 − P/100). For example, increasing 200 by 15% gives 200 × 1.15 = 230, while decreasing 200 by 15% gives 200 × 0.85 = 170. This calculator can also work backward — given the starting value and the result, it finds the percentage change; or given the percentage and the result, it finds the starting value.
Percentage difference measures how far apart two values are, relative to their average, and is always a positive number since neither value is treated as the "original." It's calculated as |V1 − V2| ÷ ((V1 + V2) / 2) × 100. This differs from percentage change, which measures the change from a specific starting value to an ending value and can be positive or negative.
Frequently Asked Questions
About this calculator
This percentage calculator covers every common percentage question in one place: the classic "P% of X" formula, quick natural-language phrasings, percentage difference between two values, and percentage increase or decrease. Each section lets you fill in any two known values and solve for the missing one, with the formula shown alongside the result.
- P% of X = Y — Solve for any one of the three values — percentage, base, or result — given the other two.
- Common phrases — "What is P% of X", "Y is what % of X", and "Y is P% of what" — answered instantly without doing the algebra yourself.
- Percentage difference — Compares two values relative to their average, always returning a positive result.
- Percentage increase/decrease — Increase or decrease a value by a percentage, or work backward from the result to find the starting value or the percentage applied.
- Step-by-step formula — Every result shows the exact formula used, so you can verify the calculation.