Three calculation modes: find what percent X is of Y, calculate percentage change, or apply a percentage to a number.
Three modes cover most percentage problems: percent of a Number (what is 25 percent of 200?), X is what percent of Y (50 is what percent of 200?), and percent Change (the increase from 100 to 150). Fill in the fields for the mode you need and click Calculate.
Useful for discounts, tax, tips, profit margins, growth rates and grade calculations. Knowing the formula helps too: X is what percent of Y is simply X divided by Y times 100, and percentage change is new minus old divided by old times 100.
Watch out for common traps: a 50 percent increase followed by a 50 percent decrease does not return to the original value, and percent off is always applied to the original price, not the discounted one.
For quick mental checks, remember that 10 percent is one tenth - shift the decimal once - and build from there. The percent change mode is especially useful for sales reports: compare this month to last month to see growth at a glance.
Calculate X% of Y
This free online percentage calculator handles all common percentage operations. Use it for sales and discounts ("What's the final price after 25% off?"), tip calculation, grade calculation, investment returns, and tax calculations. All three modes are available with instant results.
It means multiplying Y by X/100. For example, 25% of 200 = 200 × 0.25 = 50.
Percentage change = ((new - original) / original) × 100%. A positive result means an increase, negative means a decrease.
Yes. Use the "% of a Number" mode: enter the tax rate as X and the purchase amount as Y.
No. All calculations happen entirely in your browser. Nothing is sent to any server.