Percentage Calculator

Percentages show up in discounts, grades, tips, interest and statistics — but the three basic questions are easy to mix up. This calculator answers all three: what X% of a number is, what percent one number is of another, and what a number becomes after a percentage increase.

Results

Formula

The three forms all come from one relationship:
Part = Percent × Whole ÷ 100
Rearranged: Percent = Part ÷ Whole × 100, and increasing a value by P% means multiplying it by (1 + P/100).

How to use this calculator

  1. Choose the question type that matches your problem.
  2. Enter the two values (the percentage and the base, or the part and the whole).
  3. Press Calculate — the result and a plain-language restatement appear below.
  4. Use Reset to start a new problem.
Percentage Calculator — how the calculation works, illustrated%
Percentage Calculator — how the calculation works, illustrated

Worked example

What is 20% of 150?

  1. Convert the percentage to a decimal: 20 ÷ 100 = 0.20.
  2. Multiply by the base value: 0.20 × 150 = 30.

Result: 20% of 150 is 30.

Frequently asked questions

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

Divide the part by the whole and multiply by 100. For example, 30 out of 150 is 30 ÷ 150 × 100 = 20%.

What is the fastest way to calculate a percentage in my head?

Find 10% first (move the decimal one place left), then halve it for 5% or double it for 20%. Most everyday percentages can be built from 10%, 5% and 1%.

Can a percentage be more than 100%?

Yes. Whenever the part is larger than the whole — for example growth or a value compared against a smaller base — the percentage exceeds 100%.

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