PERCENTAGE CALCULATOR
Percentage calculator, share, change and margin in one place.
Compute part-to-whole shares, percent change, profit margin, weighted averages and percent conversions, with a quick reference table. Runs locally in your browser.
Quick conversion table
| Fraction | Percent | Decimal | Typical use |
|---|---|---|---|
| 1/2 | 50% | 0.5 | 一半 |
| 1/3 | 33.33% | 0.3333 | 三分之一 |
| 1/4 | 25% | 0.25 | 四分之一 |
| 1/5 | 20% | 0.2 | 五分之一 |
| 1/8 | 12.5% | 0.125 | 八分之一 |
| 1/10 | 10% | 0.1 | 十分之一 |
| 1/20 | 5% | 0.05 | 二十分之一 |
| 3/4 | 75% | 0.75 | 四分之三 |
Everything runs locally in your browser
What can this tool do?
Five common percentage calculations in one place: a part as a percentage of the whole, percent change from an old to a new value, profit margin from cost and price, a weighted average of two metrics, and conversions between decimals and percentages. A reference table of common fractions is included for quick mental checks.
FAQ
If something rises 20% then falls 20%, is it back to the start?
No. A 20% rise followed by a 20% fall gives 0.96 of the original — 4% below the start. The percentages are equal but the bases differ, so they do not cancel out.
What is the denominator of profit margin?
Profit margin is profit divided by cost, where profit equals price minus cost. If you divide by price instead, that is gross margin — a different figure.