How to Calculate Percentages (The Easy Way)
Percent of a number, percentage change, and "X is what percent of Y" — the three calculations you actually use, explained with simple examples.
Percent of a number
To find X% of a number, convert the percent to a decimal and multiply. 20% of 150 = 0.20 × 150 = 30. This is the math behind tips, discounts, and tax.
What percent is X of Y?
Divide the part by the whole and multiply by 100. If you scored 45 out of 60, that's 45 ÷ 60 × 100 = 75%.
Percentage change
Subtract the old value from the new, divide by the old value, then multiply by 100. Going from $80 to $100 is (100 − 80) ÷ 80 × 100 = a 25% increase. A negative result means a decrease.
Skip the mental math
Our Percentage Calculator handles all three cases instantly. For shopping, the Discount and Tip calculators apply the same math to real-world situations.
Try the calculators
Percentage Calculator
Calculate percentages, percentage change, and percentage of a number.
Discount Calculator
Calculate discounted price and savings for any percentage off.
Tip Calculator
Calculate tip amount and split the bill among multiple people.
Markup Calculator
Calculate selling price based on cost and desired markup percentage.