Percentage Calculator UK
Work out percentages, percentage increase, decrease and difference.
How it works
Switch modes to find a percentage of a number, what percentage one value is of another, or the percentage change between two values.
Percentage guides & tutorials
Frequently asked questions
How do I calculate X% of a number?
Divide the percentage by 100 and multiply by the number. For example, 20% of 150 is (20 ÷ 100) × 150 = 30.
How do I express one number as a percentage of another?
Divide the first number by the second and multiply by 100. For example, 45 out of 60 is (45 ÷ 60) × 100 = 75%.
How do I calculate percentage change?
Subtract the old value from the new value, divide by the old value, and multiply by 100. A rise from 200 to 250 is a 25% increase.
Why don’t a percentage rise and fall cancel out?
Because each percentage applies to a different base. A 50% decrease then a 50% increase leaves you below the start, since the increase is calculated on the smaller number.
How do I add a percentage like a percentage?
Multiply by 1 plus the rate as a decimal. To add 7% tax, multiply the price by 1.07.
What is the difference between percentage points and percent?
A change from 10% to 15% is a rise of 5 percentage points, but a 50% increase in relative terms. The two are often confused.
How to work out percentages
A percentage is just a fraction of 100. To find X% of a number Y, multiply: (X ÷ 100) × Y. To express one number as a percentage of another, divide and multiply by 100. These two operations cover the majority of everyday percentage questions, from tips and discounts to test scores and interest.
Worked examples
15% of 80 is (15 ÷ 100) × 80 = 12. If 18 students out of 24 passed, that is (18 ÷ 24) × 100 = 75%. To increase a number by 8%: 50 × 1.08 = 54.
Percentage change
To measure how much a value rose or fell, use (new − old) ÷ old × 100. A value that goes from 40 to 50 is a (50 − 40) ÷ 40 × 100 = 25% increase; going back from 50 to 40 is a 20% decrease. Note that the same absolute change is a different percentage depending on the starting point.
A common mistake
Percentage increases and decreases do not cancel out. A 50% drop followed by a 50% rise does not return you to the start: 100 falls to 50, then a 50% rise adds only 25, leaving 75. Always apply each percentage to the value that exists at that step.
Results are estimates for general guidance in United Kingdom and may not reflect the latest local rates, fees or rules. Check official sources before making decisions.