Percentage Calculator

Calculate what percentage one number is of another number.

Example: What is 25 out of 100? Answer: 25%

What this tool does

The percentage calculator solves everyday percentage problems instantly — finding what percent one value is of another, taking a percentage of a number, or working out percentage change.

The core formulas

What % is X of Y? (X ÷ Y) × 100
X% of Y? (X ÷ 100) × Y
Percentage change? ((new − old) ÷ old) × 100

For example, 18 out of 24 is (18 ÷ 24) × 100 = 75%.

How to use it

Enter the part value and the total value.
Calculate to see the percentage instantly.

Where percentages come up

Exam scores and grades
Discounts, tips and tax
Interest rates and investment returns
Statistics, surveys and data analysis

Mastering these three formulas covers the vast majority of percentage questions you'll meet day to day.

Frequently Asked Questions

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 50 is (30/50) x 100 = 60%.

How do I calculate a percentage increase?

Subtract the old value from the new value, divide by the old value, then multiply by 100.

How do I add a percentage to a number?

Multiply the number by the percentage divided by 100, then add the result to the original number.

Does this tool store my data?

No. Everything runs entirely in your browser. Nothing you enter is uploaded, saved, or shared.