Percentage Calculator
Find a percentage of a number, what share one number is of another, and both adjustments.
- 15% of 200
- 30
- 15 is what % of 200
- 7.50%
- Value plus that percentage
- 230
- Value minus that percentage
- 170
What it does
Percentage Calculator shows the whole calculation, not just the answer: every intermediate figure is on screen, so you can check it against your own numbers instead of trusting a single output box.
When you need it
Quoting, invoicing, or checking someone else's arithmetic — the moments where being roughly right costs money, and where the formula is easy to get subtly backwards.
Limits and caveats
Figures are unrounded until the final display, so results will not always match a calculation that rounded at each step. This is a working tool, not tax or financial advice, and local rules may differ. Everything happens in your browser, so the file never leaves your device.
How to use the Percentage Calculator
- Enter your numbers.
- Results update as you type.
- No rounding surprises — the maths is shown in full.
Everything happens on this device: no file is uploaded and nothing leaves the browser.
Frequently asked questions
- Why four answers?
- Because 'percentage' means four different questions depending on what you're after.
Embed this tool on your site
Copy this code into a page of your site: the calculator works inside it, nothing your visitors type is sent anywhere, and it links back here.