Percentage Calculator
Find a percentage of a number and see what percent one value is of another.
Result
How percentage calculations work
This calculator handles two common percentage questions. To find a percentage of a number, multiply the number by the percentage divided by 100. For example, 20% of 150 is 30.
To find what percent one value is of another, divide the part by the whole and multiply by 100. For example, 30 is 20% of 150. These formulas are useful for discounts, test scores, budgets, tips, commissions, growth comparisons, and everyday math.
Enter the percentage and number for the first result. Enter the part and number for the second result. Decimal values are supported when you need more precision.
Percentage calculator questions
How do I find 15% of a number?
Enter 15 in Percent and the full value in Number. The first result shows 15% of that number.
How do I find what percent one number is of another?
Put the smaller or comparison value in Part and the total or reference value in Number. The second result shows the percentage.
How do I work out a percentage in my head?
Find 10 percent by moving the decimal point one place left, then scale it. 10 percent of 150 is 15, so 20 percent is 30 and 5 percent is 7.50.
What is the formula for a percentage?
Part equals whole times percent divided by 100. Percent equals part divided by whole, times 100.
How do I add a percentage to a number?
Multiply the number by 1 plus the percent as a decimal. Adding 8 percent sales tax to $50 is 50 times 1.08, which is $54.
Worked example
Question: A $150 jacket is 20 percent off. How much do you save?
Step 1: Turn the percent into a decimal: 20 divided by 100 is 0.20.
Step 2: Multiply: 150 times 0.20 is 30.
Answer: You save $30, so you pay $120. To check it the other way, 30 divided by 150 is 0.20, which is 20 percent.