Percentage calculator
Calculate percentages quickly.
Find a percent of a number, calculate percentage change, or see what percent one number is of another for shopping, budgeting, discounts, taxes, and everyday math.
Calculator
Percentage Calculator
Choose the percentage question you are trying to answer, then enter the two numbers. The explanation below the answer updates with the calculation.
Choose a percentage calculation.
Examples
Common percentage questions
Use "What is X% of Y?" when you need a tip amount, discount amount, sales tax estimate, commission, or portion of a total. For example, 20% of 85 is 17.
Use "Percentage change from X to Y" when comparing an old value with a new value. This is useful for price changes, budget changes, traffic changes, savings growth, or business metrics.
Use "X is what percent of Y?" when comparing a part with a whole. For example, if 30 out of 120 orders were repeat customers, 30 is 25% of 120.
Percentages are often easier to compare than raw numbers because they put different totals on a common scale. A $15 increase means something different on a $50 bill than on a $500 bill.
Formulas
How each percentage result is calculated
X% of Y = X / 100 x Y
Percentage change = (new value - old value) / old value x 100
X is what percent of Y = X / Y x 100
For percentage change, a positive answer is an increase and a negative answer is a decrease. When the starting value is zero, percentage change is not meaningful because the formula requires division by the starting value.
Percentage notes
Common percentage questions
How do I calculate a discount?
Use "What is X% of Y?" to find the discount amount, then subtract that amount from the original price. For example, 25% of $80 is $20, so the sale price is $60 before tax.
How do I calculate sales tax?
Use "What is X% of Y?" with the tax rate as the percent and the taxable amount as the second number. Add the result to the original amount for the total.
Why can percentage change be negative?
Percentage change is negative when the new value is lower than the starting value. That means the value decreased.
Why does starting from zero cause a problem?
Percentage change divides by the starting value. If the starting value is zero, the formula cannot produce a normal percentage change.