Percentage Calculator: instructions, examples and limits

What it does

Result = percentage ÷ 100 × number.

Use the percentage calculator for a quick proportion, discount, markup or “what is X percent of Y?” check.

How to use it

1. 1

   Enter the percentage and the number it applies to.

2. 2

   Read the calculated amount and the formula shown below the tool.

3. 3

   For a before-and-after comparison, use Percentage Change instead so the denominator is explicit.

How the result is produced

Result = percentage ÷ 100 × number.

Important limits

Uses double-precision arithmetic; displayed values are rounded to 13 significant digits.

Checks before sharing or relying on the result

• Percent means “per hundred”; a 15% increase and a 15 percentage-point change are not always the same thing.
• Negative and decimal values can be meaningful, but the context determines whether they make sense.
• The result is arithmetic, not a recommendation about pricing or finance.

Choosing the next step

Enter values in the units and convention named by the page, then compare the displayed formula with your question. For money, change the assumptions rather than treating an estimate as an offer; for statistics, decide whether the data represents a sample or a full population.