Percentage Calculator
Free online percentage calculator. Find what X% of a number is, work out what percent one number is of another, and calculate the percentage increase or decrease between two values.
What is X% of Y?
X is what percent of Y?
Percent change from X to Y?
Percentages turn up everywhere — tips, taxes, test scores, sale prices, and growth rates — but the arithmetic is easy to fumble under pressure. This percentage calculator bundles the three questions people ask most often into one place: what is a percentage of a number, what percentage one number is of another, and how much a value has changed from one figure to the next.
Each calculator runs live in your browser as you type, so you can experiment with different numbers and see the answer update instantly. Nothing is uploaded or stored — the maths happens entirely on your device, which makes it quick to reach for whenever a percentage question comes up.
Frequently asked questions
How do I find a percentage of a number?
Divide the percentage by 100 and multiply by the number. For example, 20% of 150 is 0.20 × 150 = 30. The first calculator does this for you automatically.
How do I work out what percent one number is of another?
Divide the part by the whole and multiply by 100. So 30 out of 150 is (30 ÷ 150) × 100 = 20%. Use the second calculator to compute it instantly.
How is percentage change calculated?
Subtract the original value from the new value, divide by the original, and multiply by 100. A move from 80 to 100 is ((100 − 80) ÷ 80) × 100 = 25% — an increase. A negative result means a decrease.
Does this work offline?
Yes. Every calculation runs locally in your browser with no network requests, so it keeps working even without a connection.
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