How to work out a percentage
A percentage is just a part of 100. "15%" means 15 out of every 100. To find a percentage of a number, turn the percent into a decimal and multiply: 15% of 200 is 0.15 × 200 = 30. The first tab above does exactly that.
The three questions people actually ask
Almost every real-life percentage problem is one of three: what is X% of a number (a discount, a tip, a tax), what percent is one number of another (a score, a share), or how much did something change (a price rise, a pay increase). Each has its own tab above so you do not have to remember the formula.
Percentage change, the one people get wrong
Percentage change is always measured against the original number, not the new one. Going from 120 to 150 is a 25% rise, because the 30 increase is divided by the starting 120. A common mistake is dividing by the new number instead, which gives the wrong answer.
Frequently asked questions
How do I add a percentage to a number?
Find the percentage of the number, then add it on. To add 20% to 50: 20% of 50 is 10, so the total is 60. Tab one gives you the 10.
How do I work out a discount?
A 30%-off discount means you pay 70%. Use tab one to find 70% of the price, or find 30% and subtract it.
Is this calculator free?
Yes, completely free with no signup and nothing stored.