Percentage Calculator

Private: nothing leaves your browser

Four answers, live

What is percent of
-
is what percent of
-
From to is a change of
-
is percent of what number?
-

The four percentage questions that come up in real life, all on one page and all live as you type: a percentage of a number, one number as a percentage of another, the percentage change between two values, and working backwards from a percentage to the whole.

About this percentage calculator

Percentages are simple until you have to pick the right one. Working out 15 percent of a bill, checking that 45 marks out of 180 is a pass, seeing how much a rent rise really was, and recovering a list price from a part payment are four different sums that all sound the same when you say them out loud. All four sit side by side here, so you can read the one that matches your question instead of rearranging a formula.

The percentage change case is the one worth reading twice. It divides by the value you started from, so a rise from 1200 to 1500 is 25 percent, while a fall from 1500 back to 1200 is 20 percent. Those are not the same number, and swapping them is how a discount looks better than it is. The shop version of that trap, an inflated list price, is what the discount calculator is built to expose.

How to calculate a percentage

Find the row that matches your question. All four work at the same time.
Type your numbers into that row. The answer and the working appear under it as you type.
Negative numbers and decimals are fine. Answers are shown to four decimal places, without trailing zeros.
Press Copy answers to take every filled in row with its working.
Press Clear to empty every box and start again.

Common questions about percentages

How do I work out a percentage of a number by hand?

Divide the percentage by 100 and multiply. So 15 percent of 2500 is 0.15 times 2500, which is 375. The quick mental version is to find 10 percent by moving the decimal point one place left, halve that for 5 percent, and add the pieces you need.

Why does a 20 percent rise not cancel a 20 percent fall?

Because each one is measured against a different starting value. Add 20 percent to 100 and you get 120. Take 20 percent off 120 and you get 96, not 100, because the second 20 percent is 20 percent of the larger number. To undo a 20 percent rise you have to take off 16.67 percent.

What is a reverse percentage?

It is working back from a part to the whole. If 360 rupees is 18 percent of something, that something is 360 times 100 divided by 18, which is 2000. This is how you recover a total from a deposit, a commission or a tax line when only the part is on the paperwork.

What is the difference between percent and percentage points?

A rate that moves from 5 percent to 6 percent has risen by 1 percentage point, but by 20 percent. Both statements are true and they describe the same move, which is why reports quote whichever sounds better. When you are comparing two rates, percentage points are the honest measure.

Can it handle negative numbers?

Yes. Percentage change is measured against the size of the starting value, so a move from minus 50 to minus 25 is reported as a 50 percent increase, which is the direction the number actually moved. A starting value of zero has no percentage change at all, and that is said plainly rather than shown as an error.

Related tools

All Calculators

Discount Calculator Sale price, amount saved and the real discount percentage. GST Calculator Add or remove GST at any slab and see the split. EMI Calculator Monthly instalment, total interest and the full repayment schedule. Age Calculator Exact age in years, months and days, plus your next birthday.