Percentage calculator.
Tips, discounts, and everything in between. Figured out.
15% compared with a whole of 100%.
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What is a percentage?
A percentage is a number out of 100. So 15% means 15 out of every 100, or 0.15 as a decimal. Percentages make it easier to compare quantities, calculate tips, understand discounts and describe changes.
Find a percentage of a number.
Divide the percentage by 100, then multiply by the number. For example, a 15% tip on an 80 bill is 15 ÷ 100 × 80 = 12. The total with the tip is 92.
Find what percent one number is of another.
Divide the part by the whole and multiply by 100. If you answered 18 out of 24 questions correctly, your percentage is 18 ÷ 24 × 100 = 75%. The whole cannot be zero.
Calculate a percentage change.
Subtract the original value from the new value, divide by the absolute original value, and multiply by 100. A price moving from 80 to 100 increased by 25%. Moving back from 100 to 80 is a 20% decrease: the base is different. For negative starting values, this tool uses the absolute starting value as the denominator.
Work out a sale price.
Subtract the discount rate from 100%, then multiply the original price by the remaining percentage. For 20% off 200, the sale price is 200 × 0.8 = 160. You save 40. Two successive 20% discounts are not 40% off: 200 × 0.8 × 0.8 = 128, or 36% off.
Need to include sales tax? The discount calculator with optional tax shows your savings, rounded tax and final price in one breakdown.
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