Precision Utility
Percentage
Calculator
Three essential percentage calculations in one tool. Find a percentage of any number, work out what percentage one value is of another, or calculate the percentage change between two figures. Results update instantly as you type.
What is X% of Y?
Find a percentage of any number
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X is what % of Y?
Find the percentage ratio
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Percentage Change
From one value to another
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How the percentage calculator works
This tool covers the three most common percentage calculations. Each mode works independently — just enter your numbers and the result appears instantly.
"What is X% of Y?" multiplies the amount by the percentage and divides by 100. Use this to calculate discounts, tips, tax amounts or any proportional share.
"X is what % of Y?" divides the value by the total and multiplies by 100. Use this when you know two numbers and want to express one as a percentage of the other — exam marks, completion rates, budget proportions.
"Percentage change" computes the relative difference between an original and new value: ((new - original) / original) x 100. A positive result means an increase; negative means a decrease. Useful for tracking price changes, salary growth or performance shifts.
What you need to know about percentages
The word "percent" comes from the Latin per centum, meaning "out of one hundred." A percentage is simply a way of expressing a number as a fraction of 100.
Key concepts:
- To convert a percentage to a decimal, divide by 100 (e.g. 25% = 0.25)
- To convert a decimal to a percentage, multiply by 100 (e.g. 0.75 = 75%)
- To convert a fraction to a percentage, divide the numerator by the denominator and multiply by 100
- Percentage change can exceed 100% — a value that triples has increased by 200%
- Percentage points and percentages are not the same — moving from 10% to 15% is a 5 percentage point increase but a 50% relative increase
Percentages are used everywhere: sales tax, mortgage rates, exam scores, inflation figures, and investment returns. Understanding the three core calculations above covers the vast majority of everyday percentage problems.
Frequently asked questions
How do I find what percentage one number is of another?
Divide the part by the whole and multiply by 100. For example, 25 out of 200 is (25 / 200) x 100 = 12.5%. Use the "X is what % of Y?" mode above.
How do I calculate a percentage of a number?
Multiply the number by the percentage and divide by 100. For example, 15% of 200 is (15 / 100) x 200 = 30. Use the "What is X% of Y?" mode above.
What is the formula for percentage change?
Percentage change = ((new value - original value) / original value) x 100. A positive result means an increase, a negative result means a decrease.
What is the difference between percentage and percentage points?
Percentage points measure the arithmetic difference between two percentages. For example, going from 10% to 15% is a 5 percentage point increase but a 50% relative increase.
How do I convert a fraction to a percentage?
Divide the numerator by the denominator and multiply by 100. For example, 3/8 = 0.375 x 100 = 37.5%.
Can percentages be greater than 100%?
Yes. A percentage above 100% means the value exceeds the reference amount. For example, if a price rises from 50 to 150, that is a 200% increase.