Percentage Calculator

Find a percent of a number, what percent one number is of another, or a percent change.

Worked examples

• 15% of 200 = 200 × 15 ÷ 100 = 30
• 30 is what percent of 120? 30 ÷ 120 × 100 = 25%
• Change from 80 to 100: (100 − 80) ÷ 80 × 100 = a 25% increase
• Change from 100 to 80: (80 − 100) ÷ 100 × 100 = a 20% decrease

Notice that going up 25% and then back down needs only a 20% drop, because the percentage is always measured against the starting number.

Formulas

Percent of a number: value × percent ÷ 100. Share: part ÷ whole × 100. Percent change: (new − old) ÷ old × 100.

Frequently asked questions

How do I calculate a percentage of a number?

Multiply the number by the percentage and divide by 100. For example, 20% of 50 is 50 × 20 ÷ 100 = 10.

How do I calculate percent increase or decrease?

Subtract the old value from the new value, divide by the old value, then multiply by 100. A positive result is an increase and a negative result is a decrease.

What is the difference between percent and percentage points?

If a rate goes from 10% to 12%, it rises by 2 percentage points, but by 20 percent in relative terms (2 ÷ 10).

Why is percent change undefined when the old value is 0?

The formula divides by the old value, and dividing by zero has no result.