Percentage Calculator
Three quick calculators in one: find a percentage of a number, discover what percent one number is of another, or calculate the percentage increase or decrease between two values. Results update live as you type.
How to Use the Percentage Calculator
- Find X% of Y: enter the percentage and the number, and the result appears instantly.
- X is what % of Y: enter both values to see what percentage the first is of the second.
- Increase/Decrease: enter a starting value and an ending value to see the percentage change, labeled as an increase or decrease.
Why Use This Tool?
What's the difference between the three calculators?
"X% of Y" answers questions like "what is 20% of 250?" — useful for tips, taxes and discounts. "X is what % of Y" answers "50 out of 250 is what percent?" — useful for grades, quotas and survey results. "Increase/Decrease" answers "going from 80 to 100, what's the percentage change?" — useful for tracking growth, price changes and performance metrics.
How is percentage increase or decrease calculated?
The formula is ((New Value − Old Value) ÷ Old Value) × 100. A positive result means an increase; a negative result means a decrease. The tool automatically labels the result accordingly so you don't have to interpret the sign yourself.
Who uses percentage calculators?
Students checking exam scores, shoppers comparing discounts, employees calculating raises or commissions, analysts tracking month-over-month growth, and anyone splitting a bill or figuring out a tip all rely on quick, accurate percentage math without pulling out a spreadsheet.
Is this tool free and private?
Yes — completely free, with no signup required. All three calculators run entirely in your browser using JavaScript; nothing you enter is sent to a server or stored anywhere.