What is X% of Y?
X is what percent of Y?
Percentage Change
Increase / Decrease a Value by X%
X is Y% of what number?
What is the Percentage Calculator?
This tool covers the five most common percentage questions in one place: finding X% of a number, finding what percent one number is of another, calculating percentage change between two values, increasing or decreasing a number by a percentage, and working backward to find the original number. Each calculator updates its result instantly as you type, with no need to memorize or rearrange a formula.
How to Use It
Pick the calculator that matches your question and enter your numbers — there's no need to know the formula. "What is X% of Y" and "X is what percent of Y" give an answer as you type. "Percentage Change" compares a from-value and to-value and reports the increase or decrease along with the direction. "Increase/Decrease a Value by X%" applies a percentage in either direction to a starting number.
When to Use It
Use it to calculate a discount or markup, work out a tip or sales tax, compare this year's numbers to last year's, figure out how much a price rose or fell, or check a grade, commission, or interest calculation that's expressed as a percentage on a receipt, invoice, or report.
Who Benefits
Shoppers checking a discount, students working through percentage homework, and anyone in sales, retail, or finance who deals with percentages daily can skip the manual math and get an exact answer instantly instead of reaching for a calculator app and typing out the formula.
Percentage Formulas
| Calculation | Formula | Example |
|---|---|---|
| X% of Y | (X / 100) × Y | 20% of 250 = 50 |
| X is what % of Y | (X / Y) × 100 | 50 / 200 × 100 = 25% |
| % change A to B | ((B−A) / |A|) × 100 | (100−80)/80 × 100 = 25% |
| Y + X% | Y × (1 + X/100) | 500 × 1.20 = 600 |
| Y − X% | Y × (1 − X/100) | 500 × 0.80 = 400 |
| X = Y% of ? | (X / Y) × 100 | 45 / 0.30 = 150 |