How to use the percentage calculator

Select the calculation you need, enter the two numbers and choose Calculate. The tool supports percentage-of, part-to-whole percentage and percentage change.

Percentage formulas

• X% of Y: (X ÷ 100) × Y
• X is what percent of Y: (X ÷ Y) × 100
• Percentage change: ((New − Original) ÷ |Original|) × 100

Example

15% of 200 is 30. To find what percentage 30 is of 200, divide 30 by 200 and multiply by 100 to get 15%.

Worked examples

Find 15% of $200: Divide 15 by 100, then multiply by 200. The result is $30.

Find what percent 30 is of 200: Divide 30 by 200 and multiply by 100. The result is 15%.

Calculate a change from 80 to 100: (100 − 80) ÷ 80 × 100 = 25% increase. A change from 100 to 80 is a 20% decrease.

The percentage-change mode divides by the absolute value of the original number. When the starting value is negative, interpret the direction in the context of the measurement rather than treating the percentage as a financial return.

Frequently asked questions

Can I calculate a percentage increase? Yes. Select percentage change and enter the original and new values. A positive result is an increase; a negative result is a decrease.

Does this calculator round results? Results are displayed to two decimal places where needed. The calculation uses the entered values.

Related guide: How to calculate percentage increase explains the formula with more examples.