Percentages turn up everywhere: sale discounts, pay rises, exam marks, tax, tips, investment returns and growth charts in a business report. This free percentage calculator handles the four questions people actually search for, each in its own box so you don't have to rearrange formulas in your head. Find what X% of a number is (for example, 15% of 80). Work out what percent one number is of another (18 out of 24). Calculate the percentage increase or decrease between an old and a new value, which is how price changes and growth are reported. And add or subtract a percentage from a number, for things like adding 20% VAT in the UK or knocking 30% off a price. Every answer shows the working in plain English, so students can follow the method and you can double-check it. A common trap we flag: a 50% fall followed by a 50% rise does not get you back to where you started. The calculator updates as you type, works on phones, and runs entirely in your browser with nothing uploaded.
Percentage calculator
How to calculate percentages
- X% of Y = X ÷ 100 × Y.
- X as a % of Y = X ÷ Y × 100.
- Percentage change = (new − old) ÷ old × 100.
- Add X% = Y × (1 + X/100); remove X% = Y × (1 − X/100).
Percentage vs percentage points
If a rate goes from 4% to 5%, it rose by 1 percentage point but by 25 percent. News and finance reports mix these up all the time.
FAQ
How do I remove VAT from a price?
Divide by 1 plus the rate, not multiply by 1 minus it. For 20% UK VAT, £120 ÷ 1.2 = £100. Subtracting 20% from £120 would wrongly give £96.
Why doesn’t −50% then +50% get back to the start?
Because the second percentage is taken from a smaller number. 100 − 50% = 50, and 50 + 50% = 75.
Can the percentage change be over 100%?
Yes. Going from 20 to 60 is a 200% increase. A decrease can’t be more than 100% for positive values.
Is anything saved?
No, it all runs in your browser.
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