Percentage Calculator
Work out percentages, increases and discounts in one click.
Percentages show up everywhere — tips, taxes, discounts, grades and statistics.
How to use
- Pick the calculation you need using the tabs.
- Enter your two numbers and click Calculate.
- Use "% change" for price rises, salary bumps and growth rates.
About this tool
The three most common percentage questions are: what is X% of a number, what percent one number is of another, and how much something changed in percent terms.
This calculator answers all three instantly, with no sign-up and no data stored.
How it works
A percentage is just a fraction out of 100, so every percentage question boils down to one of three moves. To find X% of a number, multiply the number by X and divide by 100. To find what percent one number is of another, divide the first by the second and multiply by 100.
Percentage change needs one extra step: subtract the old value from the new value, divide by the old value, then multiply by 100. A positive result is an increase, a negative one a decrease. The classic mistake is dividing by the new value instead of the old — always divide by where you started.
Worked examples
What is 20% of 80?: Multiply 80 by 20, then divide by 100: 80 x 0.20 = 16. So a 20% tip on an $80 bill is $16.
Price rise from $60 to $75 — what percent increase?: Subtract first: 75 - 60 = 15. Divide by the original: 15 / 60 = 0.25. Multiply by 100: 25%. The price went up 25%.
Quick reference
| Question | Formula |
|---|---|
| X% of Y | (X / 100) x Y |
| X is what % of Y | (X / Y) x 100 |
| % change from A to B | ((B - A) / A) x 100 |
| X% off a price P | P x (1 - X / 100) |
Frequently asked questions
How do I calculate 20% of 80?
Multiply 80 by 0.20 — the answer is 16. Or use the first tab above.
How do I find percentage increase?
Subtract the old value from the new value, divide by the old value, and multiply by 100. The third tab does this for you.
Is my input stored anywhere?
No — all calculations run in your browser.
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