Percentage calculator
Pick what you want to work out, type two numbers and the answer appears at once, with the working shown so you can check it or copy the method. Everything runs in your browser.
Everything runs on your device. Nothing you add or type is sent to any server.
How to use it
- 01
Choose a mode: X % of Y, X is what % of Y, % change, add or subtract a %, or marks percentage.
- 02
Type the two numbers. Commas are fine, like 10,00,000, and you can use decimals in every mode and negative numbers in every mode except marks.
- 03
Read the answer and the working line under it. Switch modes any time; each mode keeps its own numbers.
The formulas, with worked examples
X % of Y = Y × X ÷ 100. For example, 15 % of 2,000 is 2,000 × 15 ÷ 100 = 300.
X is what percent of Y = X ÷ Y × 100. For example, 45 out of 250 is 45 ÷ 250 × 100 = 18 %.
Percentage change from A to B = (B − A) ÷ A × 100. A price going from 500 to 650 is (650 − 500) ÷ 500 × 100 = a 30 % increase. A negative answer means a decrease. If A is negative, the calculator divides by its size without the minus sign, so a rise still reads as an increase.
Adding a percentage: Y + Y × X ÷ 100. So 1,000 plus 18 % is 1,000 + 180 = 1,180. Subtracting works the same way with a minus.
Marks percentage
Divide the marks you got by the maximum marks and multiply by 100. For example, 432 out of 500 is 432 ÷ 500 × 100 = 86.4 %. The result is shown to two decimal places. Your board or university may round differently or calculate percentage from selected subjects only, so check its rules before you fill in a form.
A common trap
Adding a percentage and then taking the same percentage off does not bring you back to the start. 100 plus 10 % is 110, but 110 minus 10 % is 99, because the second 10 % is taken from a bigger number. To find the original price from a price that already includes a percentage, divide instead: 110 ÷ 1.10 = 100.
Frequently asked questions
How many decimal places are shown?
Up to four decimal places, with Indian digit grouping, and trailing zeros are dropped. The marks mode shows up to two decimal places.
Why do I get an error when the first number is 0 in the change mode?
A change from 0 cannot be expressed as a percentage, because it would mean dividing by zero. The same applies when the whole is 0 in the what-percent mode.
Is my data stored anywhere?
No. The calculator runs entirely in your browser, and nothing you type is sent or saved.