What is X% of Y?
TOOLType a percentage and a number to find the result instantly.
Finding a percentage of a number is one of the most common everyday calculations — working out a tip, a discount, a tax, or a share of a total all come down to the same single step. This tool answers the question "what is X% of Y?" the moment you type, so you never have to reach for a separate calculator.
The formula
To find a percentage of a number, convert the percentage to a decimal by dividing it by 100, then multiply by the number:
result = (X ÷ 100) × Y
Because "percent" means "per hundred," 25% is the same as the decimal 0.25 or the fraction 25/100. So 25% of 80 becomes 0.25 × 80 = 20. The same recipe works for any values: 8% of 250 is 0.08 × 250 = 20, and 150% of 80 is 1.5 × 80 = 120 — a percentage above 100 simply means more than the whole.
Some percentages are quick to do in your head. 10% of any number is that number with the decimal point moved one place left. 50% is half. 25% is half of a half. You can combine these — 15% is "10% plus half of that 10%."
A worked example
Imagine a total of 80 items and you want to know how many fall into a category that makes up 25% of them. Multiply: 0.25 × 80 = 20 items. If a second category is 40% of the same 80, that is 0.40 × 80 = 32 items. Add the two and you have accounted for 52 of the 80, leaving 28 (or 35%) for everything else. This is how a single total gets broken down into parts you can compare.
Where percentages become charts
The moment you express parts of a total as percentages, you have the exact data a composition chart needs. In a pie chart the full circle stands for 100%, so a 25% category claims a quarter of the circle and a 40% category claims a little under half. Computing "X% of Y" for each category is the bridge between a raw total and a clear visual of how that total splits up.
When you have your shares, the pie chart maker draws and exports the pie for you, or use make a chart to choose a bar chart instead if you would rather compare the percentages as bars. For the inverse question — turning a fraction straight into a percentage — try the fraction to percentage converter.