Discount Calculator
Find the sale price and how much you save.
Sales Tax Calculator
Find the tax amount and total price at checkout.
VAT Calculator
Add or remove VAT from a price.
What is X% of Y?
Find the value of a percentage of any number.
X is what percent of Y?
Find what percentage one number is of another.
Percentage increase or decrease
Find the percentage change from one value to another.
How percentage calculations work
A percentage is just a fraction of 100 — understanding these calculations covers almost every real-world percentage problem, from working out a discount at checkout to tracking growth in a spreadsheet.
Finding a percentage of a number
Divide the percentage by 100, then multiply by the number. 20% of 150 is (20 ÷ 100) × 150 = 30. This is the calculation behind working out a discount, a tip, or a tax amount.
Finding what percent one number is of another
Divide the first number by the second, then multiply by 100. 30 is what percent of 120? (30 ÷ 120) × 100 = 25%. Useful for grades, conversion rates, and completion rates.
Percentage increase or decrease
Subtract the original value from the new value, divide by the original value, then multiply by 100. Going from 80 to 100 is a 25% increase. This is the formula behind salary rises, price changes, and growth metrics.
How to calculate a discount
Multiply the price by the discount percentage divided by 100 to get the amount you save, then subtract that from the price. A 25% discount on 80 saves 20, for a final price of 60.
How to calculate sales tax
Multiply the pre-tax price by the tax rate divided by 100 to get the tax amount, then add that to the price. 100 at an 8.25% tax rate adds 8.25 in tax, for a total of 108.25.
How to add or remove VAT
To add VAT: multiply the net price by the VAT rate divided by 100, then add that to the price. To remove VAT from a price that already includes it: divide the price by (1 + VAT rate ÷ 100) to find the net amount.