Percentage Calculator
Five percentage questions, one tool. Pick what you want to find, type two numbers, and see the answer with the formula filled in.
- Runs in your browser
- Five modes
- Formula shown
- Free
Percentage calculator
The five percentage formulas
X% of Y
Y × X ÷ 100. 35% of 80 = 80 × 0.35 = 28.
X is what % of Y
X ÷ Y × 100. 40 out of 60 = 66.7%.
Percent change, difference, error
Change: (new − old) ÷ old × 100. Difference: |a − b| ÷ average × 100. Error: |measured − accepted| ÷ accepted × 100.
Questions people ask
How do you calculate the percentage of a number?
Multiply the number by the percent and divide by 100. 35% of 80 is 80 × 35 ÷ 100 = 28. Or turn the percent into a decimal first: 80 × 0.35.
How do I find what percent one number is of another?
Divide the part by the whole and multiply by 100. 40 is 40 ÷ 60 × 100 = 66.7% of 60.
How do you calculate percentage difference between two numbers?
Take the difference, divide by the average of the two, multiply by 100. For 50 and 75: 25 ÷ 62.5 × 100 = 40%. Use percent change instead when one value is clearly the "before".
How do you calculate percent error?
|measured − accepted| ÷ accepted × 100. Measuring 9.8 when the true value is 10 gives 2% error.
How do I take a percentage off a price?
Work out the percent of the price and subtract it, or multiply by (1 − percent). 20% off $50 is $50 × 0.8 = $40.