Percentage Calculator
Percentages, discounts and changes, without remembering the formulas.
About this tool
Sale discounts, rent rises, pay increases, a share of a total: percentages are everywhere, and so are the mistakes. This calculator covers the cases that actually come up — X% of a value, what percentage X is of Y, the change between two numbers, and the final price after a discount — with the working shown so you can see how the answer was reached.
Every result is computed instantly in your browser, and each mode is a single tap away. Free, no account, nothing transmitted.
Frequently asked questions
How do I calculate a percentage change?
(Final value − starting value) ÷ starting value × 100. Going from 80 to 100 is +25%, but going back from 100 to 80 is −20%: percentage changes are not symmetrical, which trips people up constantly.
Does a 50% rise followed by a 50% fall cancel out?
No. $100 plus 50% is $150, and 50% off that is $75. Successive percentages multiply rather than add, which is exactly why it is worth checking here.
How do I work out a price after a discount?
Price × (1 − discount/100). An item at $60 with 30% off costs 60 × 0.70 = $42, and you saved $18.
How do I find what percentage one number is of another?
Divide the part by the whole and multiply by 100: 45 out of 180 is 45 ÷ 180 × 100 = 25%. The “X is what % of Y” mode does it for you.
Is it really free, with no sign-up?
Yes — the tool is free, needs no account and has no usage limit. Processing happens locally in your browser, so your data never leaves your device.