Percentage Calculator

Calculate percentage of a number, percentage increase or decrease, and what percent one value is of another with this free online percentage calculator.

Everything runs in your browser. Your input is not sent to a server.

How to use the Percentage Calculator

Choose the calculation type you need (percentage of a number, increase/decrease, or “X is what percent of Y”).
Enter the required values in the fields.
Press Calculate to see the result instantly.
Copy the answer or reset the form for a new calculation.

How it works

Percentages express a number as a fraction of 100. This tool applies the standard formulas: (part ÷ whole) × 100, or original × (1 ± rate/100) for increase and decrease.

Useful for discounts, markups, exam scores, statistics and everyday “what percent is this of that” questions.

Examples

What is 15% of 200? → 30.
A price rises from 80 to 100 → 25% increase.
40 is what percent of 160? → 25%.

Percentage Calculator FAQ

How do I calculate percentage of a number?

Enter the percentage and the base number, then press Calculate. The result is (percentage ÷ 100) × number.

Can I calculate percentage increase and decrease?

Yes. Enter the original and new values (or the rate) depending on the mode you select.

Is the result exact?

Results use normal floating-point arithmetic in your browser and are suitable for everyday calculations.

Is it free?

Yes. No account or download is required.