Percentage Calculator

Find what X% of Y is, calculate percentage change and reverse percentages in seconds.

100% private Instant results No sign-up Updated Aug 12, 2026

About this tool

Work out any percentage problem in one place: percentage of a number, percentage increase or decrease, and reverse percentages. Ideal for shopping discounts, grade calculations, budgets and growth metrics.

How it works

The calculator uses three standard formulas. For "X% of Y", it computes Y × X ÷ 100. For "X is what % of Y", it computes X ÷ Y × 100. For percentage change between A and B, it computes (B − A) ÷ A × 100. Results are rounded to up to four decimal places and, when sensible, shown as a fraction or ratio too.

How to use Percentage Calculator

1Pick the mode that matches your question: "X% of Y", "X is what % of Y", "Percentage change", or "Reverse percentage".
2Enter your numbers into the labelled fields. Invalid or empty values show a helpful inline message.
3The result updates instantly as you type, with a full step-by-step breakdown below it.
4Use the copy button to copy the answer, or reset to start a fresh calculation.

Examples

What is 18% of 250? Answer: 45.

If your salary goes from 40000 to 46000, the increase is 15%.

A shirt costs 60 after a 25% discount, so the original price was 80.

You scored 42 out of 50 on a test — that is 84%.

Pro tips

For discounts, switch to the Discount Calculator — it also shows the amount you save.
To split a bill including tip, the Tip Calculator combines both in one step.
When calculating percentage change, keep the order of your numbers straight: change is always relative to the starting value.