Percentage Calculator
Work out percentages four ways — a percentage of a number, one number as a percentage of another, percentage change, and increasing or decreasing a number by a percentage — with the working shown for every answer.
Calculate a percentage
Pick the type, enter your numbers — an answer with its working is ready below.
Your result and the working will appear here.
Four calculations, one page
The percentage questions people actually ask, each with its working.
Percent of a number
What is 20% of 150? The most common percentage question there is, answered with its working.
Shares and changes
One number as a percentage of another, and the percentage change between two values.
Increases and decreases
Pay rises, price rises and growth rates — apply a percentage change in either direction.
About this percentage calculator
Percentages turn up everywhere: exam marks, sale prices, pay rises, tax, tips, interest and statistics. Almost every question is one of four shapes — finding a percentage of a number, expressing one number as a percentage of another, measuring the percentage change between two values, or increasing or decreasing a number by a percentage — so this calculator covers all four, and shows the working for each answer instead of just the result.
The methods are the standard ones. A percentage of a number is the number multiplied by the percentage and divided by 100. One number as a percentage of another is the first divided by the second, times 100. Percentage change is the difference divided by the starting value, times 100 — the step people most often get wrong, because dividing by the new value instead gives a different, incorrect figure.
For sale prices and stacked discounts specifically, the Discount Calculator is the better fit — it works out the price you pay and what you save. This page is the general-purpose percentage tool for everything else.
Frequently asked questions
The standard methods, explained the way the calculator uses them.
How do I calculate a percentage of a number?
Multiply the number by the percentage, then divide by 100. For example, 20% of 150 is 150 x 20 / 100 = 30. The first tab does this for you and shows the steps.
How do I work out one number as a percentage of another?
Divide the first number by the second and multiply by 100. For example, 45 out of 180 is 45 / 180 x 100 = 25%. Use the second tab.
How is percentage change calculated?
Take the difference between the new and old values, divide it by the old (starting) value, and multiply by 100. Going from 80 to 100 is a difference of 20, and 20 / 80 x 100 = a 25% increase. Dividing by the starting value — not the new one — is what makes it correct.
How do I increase a number by a percentage?
Work out the percentage of the number and add it on. To increase 200 by 15%: 15% of 200 is 30, so the answer is 230. Decreasing works the same way, taking the amount away instead. The fourth tab does both.
What is the difference between percentage change and percentage points?
Percentage points measure the simple difference between two percentages: a rate rising from 4% to 5% is up 1 percentage point. The percentage change is relative: that same rise is a 25% increase (1 / 4 x 100). News reports confuse the two often.
Is this calculator free, and are my numbers private?
Yes — it is free with no sign-up, and the calculation runs entirely in your browser, so the numbers you enter are never uploaded or stored.