Percentage Calculator

Multiply the number by the percentage divided by 100. For example, 20% of 150 is 150 × 0.20 = 30. Use the “P% of X” mode above.

Divide the first number by the second and multiply by 100. For example, 45 is (45 ÷ 180) × 100 = 25% of 180. Use the “X is what % of Y” mode.

Subtract the old value from the new value, divide by the old value, and multiply by 100. Going from 50 to 75 is a 50% increase. Use the “% increase / decrease” mode.

Same formula as increase — the result is negative. Going from 80 to 60 is a −25% change, i.e. a 25% decrease.

Divide 30 by 20% (0.20) to get 150. Use the “X is P% of what?” mode for reverse percentage problems.

Multiply by 1 plus the percentage as a decimal: 200 increased by 15% is 200 × 1.15 = 230. Use the “Increase / decrease by %” mode.

A change from 20% to 25% is a 5 percentage-point rise, but a 25% relative increase (5 ÷ 20). News and statistics usually mean percentage points; this calculator shows the relative percent change.

Yes — “P% of X” handles tips (18% of a $64 bill), and “Increase / decrease by %” handles discounts (price decreased by 30%). A dedicated tip calculator is also on the way.

No. Every calculation happens in your browser; nothing you type is sent to a server or stored.

Some percentages don't divide evenly (e.g. 10 ÷ 3 = 3.333…%). The calculator shows up to 10 significant digits so you can round to whatever your class or context needs.