How do I find a percentage of a number?

Use "X% of Y" mode. Enter the percentage (X) and the number (Y). The result is (X / 100) × Y.

How do I calculate percent change?

Use "% change from X to Y" mode. The formula is ((Y − X) / |X|) × 100. A positive result is an increase; negative is a decrease.

Yes. All modes support negative and decimal numbers.

The result is Y × (1 + X / 100). For example, 150 + 10% = 150 × 1.10 = 165.

It returns (X / Y) × 100. For example, 30 is what % of 150 = 20%.

Choose a mode, enter two values, and get the result instantly.

Mode

X% of Y

e.g. 20% of 150 = 30

X is what % of Y

e.g. 30 is what % of 150?

% change from X to Y

e.g. from 100 to 120 = 20% increase

Add X% to Y

e.g. 150 + 10% = 165

Value X (%)

Value Y

Real-time calculation

Enter values on the left to see results instantly.

Supports decimals and negative numbers.

Choose a mode, enter two values, and get the result instantly.

Last updated: 2026-09-14 · Reviewed by Nham Vu