Math
Percentage calculator
Four universal percent operations: find X% of a number, find what percent one number is of another, compute percent change, and add/subtract a percent of a base.
Formula
A percent is one hundredth of a number. The % symbol is shorthand for multiplication by 0.01 — so 15% means 0.15.
All calculations run in your browser at full JavaScript precision (~15 significant digits) with no intermediate rounding. The display rounds to 4 decimal places and strips trailing zeros, but the underlying value keeps every digit.
Common uses: store discounts, supplier markups, sales tax, tips, year-over-year growth, percent change of a stock price, share of survey respondents.
Examples
- 01What is 15% of 200?→ 0.15 × 200 = 30
- 0230 is what percent of 200?→ 30 ÷ 200 × 100 = 15%
- 03What is the % change from 100 to 130?→ (130 − 100) ÷ 100 × 100 = +30%
- 04What is 100 + 15%?→ 100 + 100 · 0.15 = 115
FAQ
- If a rate moves from 5% to 8%, that's +3 percentage points, but +60 percent in relative terms (since (8−5)/5 = 0.6). Central banks and finance reports use percentage points to avoid this ambiguity.
References
Note: Results are accurate to floating-point precision (~15 significant digits) for the standard formula shown above. See our terms of use for general usage information.