Percentage Calculator
Work out any percentage, change or markup.
How to use
- 1 Choose the kind of percentage calculation you need.
- 2 Enter the two values the calculation asks for.
- 3 Read the result, formatted and rounded for you.
- 4 Copy the answer to use elsewhere.
About Percentage Calculator
The Percentage Calculator handles the five percentage questions that come up again and again, without you having to remember which way the formula goes.
Find what X% of a value is, work out what percentage one number is of another, measure the percentage change between two figures, or increase and decrease a value by a chosen percent.
Percentages are everywhere — a discount in a shop, a tip on a bill, a tax added to a price, a year-on-year change in a report, a grade as a share of total marks.
Each of these is a slightly different calculation, and it is easy to divide the wrong way round or forget whether to add the percentage back on.
This tool keeps each mode separate and clearly labelled, so you pick the question you are actually asking and just type the two numbers.
Every result is rounded to remove floating-point noise and comes with a copy button, so you can paste it straight into a spreadsheet, an invoice or a message.
The maths runs entirely in your browser — nothing is sent anywhere — and the same inputs always produce the same answer, so you can trust it for quick mental checks as much as for real work.
FAQ
How do I find what percent one number is of another?
Pick the "X is what % of Y" mode, enter the part and the total, and the tool divides the part by the total and multiplies by 100.
What does percentage change measure?
It measures how much a value has grown or shrunk relative to its starting figure, expressed as a percent. A negative result means a decrease.
Is my data sent anywhere?
No. Every calculation runs locally in your browser, so the numbers you type never leave your device.