Percentage Calculator
Find percentages, changes & ratios instantly.
100% private — runs in your browser, nothing is uploaded.
What is X% of a number?
X is what percent of Y?
Percentage increase or decrease
How to use the Percentage Calculator
- 1Pick the calculation you need
There are three calculators: percent of a number, one number as a percent of another, and percentage increase or decrease.
- 2Enter your numbers
Type the values into the boxes. Results update instantly — there is no calculate button to press.
- 3Read the answer
The highlighted result line spells out the full calculation so you can double-check it at a glance.
- 4Reuse or adjust
Change any value to recalculate, or use a different section for a different type of percentage problem.
Examples
| Input | Output |
|---|---|
15% of 200 | 30 |
25 is what % of 200 | 12.5% |
120 → 150 | 25% increase |
Free online percentage calculator
This percentage calculator solves the three most common percentage problems in one place: finding a percentage of a number, expressing one number as a percentage of another, and working out the percentage increase or decrease between two values. Everything updates live as you type.
Everyday uses
- Calculating discounts, tips, taxes and VAT.
- Working out test scores, grades and pass marks.
- Measuring growth — sales, weight, followers or prices over time.
- Comparing figures in reports, budgets and spreadsheets.
The formulas
Percent of a number: (percent ÷ 100) × number. One number as a percent of another: (part ÷ whole) × 100. Percentage change: ((new − old) ÷ old) × 100. Because the tool runs entirely in your browser, your numbers stay private and it keeps working even without an internet connection.
Frequently Asked Questions
How do I calculate a percentage of a number?
Divide the percentage by 100 and multiply by the number. For example, 15% of 200 is (15 ÷ 100) × 200 = 30. The first box on this page does this automatically as you type.
How do I find what percent one number is of another?
Divide the first number by the second and multiply by 100. For example, 25 is (25 ÷ 200) × 100 = 12.5% of 200. Use the second calculator for this.
How is percentage increase or decrease calculated?
Subtract the old value from the new value, divide by the old value, then multiply by 100. Going from 120 to 150 is ((150 − 120) ÷ 120) × 100 = 25% increase.
What is the difference between percentage and percentage points?
A percentage point is the plain difference between two percentages. Going from 10% to 15% is a 5 percentage-point rise, but a 50% relative increase. This tool reports the relative percentage change.
Is my data sent to a server?
No. Every calculation runs in JavaScript inside your browser. Nothing you type is uploaded or stored, so it is completely private and works offline.
Can it handle decimals and negative numbers?
Yes. You can enter decimals like 12.5 and negative values. Percentage change correctly shows a decrease when the new value is lower than the old one.