Free Online Percentage Calculator

Calculate percentages, increases, decreases and original values instantly.

Use the percentage calculator to solve the most common percentage problems: find a percentage of a number, determine what percentage one value is of another, or measure an increase or decrease between two values.

For example, 15% of 200 is calculated as 0.15 × 200 = 30. To find what percentage 40 is of 50, divide 40 by 50 and multiply by 100, giving 80%.

How to use this tool

  1. Select percentage of, percentage change, or rate and ratio mode.
  2. Enter both values in the labeled fields.
  3. Read the result immediately and check the displayed formula.
  4. Save useful calculations to the history stored in your browser.

Frequently asked questions

How do I calculate a percentage of a number?

Convert the percentage to a decimal and multiply it by the number. For 15% of 200, calculate (15 ÷ 100) × 200 = 30.

How is percentage change calculated?

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

How do I find what percentage one number is of another?

Divide the part by the whole and multiply by 100. If 40 questions out of 50 are correct, (40 ÷ 50) × 100 = 80%.