Percentage Calculator
Local ProcessingCalculate what is P percent of number X instantly.
How It Works & Processing Standards
Enter values above to calculate results automatically. Check each input field for guidance and units.
Example: Base Number = 200, Percentage Rate (%) = 15 → 30
Tool processing runs in your browser. If you create a calculator or conversion share link, its values are included in the URL. See the privacy policy for account, analytics and advertising data.
Pick what you need under "Calculation" and type the numbers. One tool covers four percentage calculations, from "what is 15% of" to achievement rates and the gap between two measurements.
What You Can Do
- Percent of a value
- base × rate ÷ 100 — for example 15% of an amount or 30% of a headcount.
- Part of the whole
- part ÷ whole × 100 — achievement against a target or a share.
- Percent difference
- |a − b| ÷ the average of both × 100 — how far apart two values are when neither is the reference.
- Percent error
- |observed − true| ÷ |true| × 100 — how far a measurement is from the reference.
How to Use Percentage Calculator
- 1Choose a calculationPick one of the four under "Calculation". Only the fields it needs are shown.
- 2Enter numbersThe result updates as you type. Negative numbers and decimals are accepted.
- 3Copy or shareCopy the result or create a share link that reopens the same inputs.
Examples
Common Use Cases
- Working out a discount, fee or tax as part of an amount
- Sales target achievement, test scores or market share
- Comparing how far apart two measurements or two prices are
Frequently Asked Questions (FAQ)
How is percent difference different from percent change?
Percent change uses the old value as the reference. Percent difference uses the average of both, so swapping them gives the same result. Going from 80 to 100 is a 25% increase but a 22.22% difference.
What happens if the whole is 0?
Division by zero is not possible, so you are asked to check the input instead. The same applies to the true value in percent error.