Percentage Calculator
Work out percentages of, changes, and shares in one place.
Your answer appears here
Pick a mode and enter your numbers. The percentage result updates live as you type — right here in your browser, with nothing sent to a server.
Runs entirely in your browserCalculate percentages three ways, locally
This calculator covers the three questions people ask about percentages. Pick a mode, type your numbers, and the answer updates as you type. “X% of Y” finds a portion of a total — like a tip or a discount amount. “X is what % of Y” turns a part and a whole into a percentage — like a test score. “% change from X to Y” measures growth or shrinkage between two values. Everything runs in your browser and nothing is uploaded.
Common questions
How do I find X percent of a number?
Choose the “X% of Y” mode, enter the percentage in the first box and the total in the second. For example 15% of 200 is 30. The result updates instantly as you type.
How do I work out what percent one number is of another?
Pick the “X is what % of Y” mode, enter the part first and the whole second. For example 45 is 90% of 50. This is how you turn a score like 45 out of 50 into a percentage.
How is percent increase or decrease calculated?
In the “% change” mode, enter the starting value and the ending value. The tool computes (end − start) ÷ start × 100. A positive result is an increase, a negative result is a decrease.
Why do I see “—” instead of a result?
That appears when a required box is empty or when a calculation would divide by zero (for example asking what percent something is of 0). Fill in valid numbers and the answer appears.
Are my numbers sent anywhere?
No. The math runs entirely in your browser with JavaScript. Nothing you type is uploaded or stored on a server.