Percentage Calculator

A percentage is a number out of 100. This percentage calculator finds a percentage of a number, works out what percent one number is of another, finds the original whole from a part, and increases or decreases a value by a percentage. Every answer shows the working and is checked by reversing the calculation.

Try:

How to use the percentage calculator

  1. Choose what you want to find, such as X% of Y.
  2. Enter the two numbers X and Y.
  3. Press Calculate to see the answer, the steps and how it was checked.

Formula

Part=Percent100×Whole\text{Part} = \frac{\text{Percent}}{100} \times \text{Whole}
Percent=PartWhole×100\text{Percent} = \frac{\text{Part}}{\text{Whole}} \times 100

Worked example: 20% of 150

  • What do you want to find?: X% of Y
  • X: 20
  • Y: 150

✓ Answer checked

3030
20 out of every 100 squares are shaded: that is 20%.
Step-by-step working (2 steps)

  1. Turn the percentage into a decimal Per cent means out of 100

    Divide the percentage by 100.

    20%=20100=0.220\% = \frac{20}{100} = 0.2

  2. Multiply

    Multiply by 150.

    0.2×150=300.2 \times 150 = 30
Formulas used
Part=Percent100×Whole\text{Part} = \frac{\text{Percent}}{100} \times \text{Whole}
How this was checked
  • ✓ 30 is 20% of 150, checked by working out 30 ÷ 150 × 100.

Frequently asked questions

How do I calculate a percentage of a number?

Divide the percentage by 100 and multiply by the number. For example, 20% of 150 is 0.2 × 150 = 30.

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

Divide the part by the whole and multiply by 100. For example, 45 out of 60 is 45 ÷ 60 × 100 = 75%.

How do I add a percentage to a number?

Multiply by 1 plus the percentage as a decimal. To add 15% to 80, work out 80 × 1.15 = 92.

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