Percentage Calculator
Solve the three most common percentage questions instantly — all in one place, all in your browser.
Three calculators in one
The first row finds a percentage of a number (what is 20% of 150). The second finds what percentage one number is of another (30 is what % of 150). The third finds the percentage change between two numbers — handy for price changes, grades, statistics and more.
Frequently asked questions
How do I find X% of a number?
Multiply the number by the percentage divided by 100. For example, 20% of 150 = 150 × 0.20 = 30. The first box does this for you.
How do I find what percent one number is of another?
Divide the part by the whole and multiply by 100. For example, 30 out of 150 = (30 ÷ 150) × 100 = 20%. The second box handles this.
How is percentage increase or decrease calculated?
Subtract the old value from the new, divide by the old value, then multiply by 100. A positive result is an increase, a negative one a decrease.
Is anything uploaded?
No. Every calculation runs in your browser — your numbers stay on your device.