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Percentage Calculator
Three handy percentage tools in one place — find X% of Y, work out what percent one number is of another, and calculate percentage change. Free and instant.
What is X% of Y?
X is what percent of Y?
Percentage increase / decrease
How to use the percentage calculator
- Pick the mini-tool you need — X% of Y, X as % of Y, or percentage change.
- Type your numbers into the boxes.
- Each answer updates live as you type — no buttons needed.
About percentages
A percentage is simply a number expressed as a fraction of 100. Percentages show up everywhere: discounts in shops, interest on savings, tips at restaurants, tax rates and test scores.
Most percentage problems are one of three types, which is why this page bundles all three tools together. If you can recognise which type you are facing, the answer is one calculation away.
Percentage FAQs
How do you find X% of Y?
Multiply X by Y and divide by 100. For example, 20% of 150 is 20 × 150 ÷ 100 = 30.
How do you find what percent X is of Y?
Divide X by Y and multiply by 100. For example, 45 is (45 ÷ 150) × 100 = 30% of 150.
How is percentage increase or decrease calculated?
Subtract the old value from the new value, divide by the old value and multiply by 100. A positive answer is an increase; a negative one is a decrease.
What is the difference between percent and percentage points?
A rise from 20% to 25% is a 5 percentage-point rise, but a 25% increase (5 ÷ 20). Mixing the two up is the most common percentage mistake.