Best for percentage math
Use Percentage Calculator for discounts, tax, tips, grade changes, price increases, commissions, and comparison calculations.
About Percentage Calculator
Four percentage questions that come up all the time, all answered in one page. What is 15% of 200? What percentage is 30 of 150? What's the percentage change from 80 to 100? What's 250 increased by 20%? Each one shows the result instantly as you type, along with the full formula and the numbers substituted in - so you can actually verify it rather than just trust a number that appeared. Useful for discounts, tax, tips, price changes, grades, commission, and anything else where percentages trip people up. Everything runs in your browser.
Percentage Calculator details
Four calculation modes
The tool supports percent of a number, what percent one value is of another, percentage increase or decrease, and adding or subtracting a percent.
Formula shown
Each mode displays the formula with your numbers inserted so the result can be checked instead of treated as a black box.
Client-side privacy
Calculations run locally in the browser and the entered numbers are not uploaded.
Limits and rounding
Very large or very small decimal inputs follow normal browser number precision. Displayed results are rounded for readability.
Common percentage mistakes
Check whether you need percentage points, percent change, or percent of a number; those are different calculations.
How it works
1
Choose the calculation type
Pick the percentage question that matches what you're trying to solve.
2
Enter the numbers
Type the values and the result updates live as you type.
3
Check the formula
The exact formula with your numbers substituted is shown under the result so you can verify it.
Frequently asked questions
Which percentage calculations are included?
Percent of a number (X% of Y), percentage of one value relative to another, percentage increase or decrease between two values, and adding or subtracting a percentage from a value.
Does it show how the result was calculated?
Yes - every mode displays the formula with your numbers filled in, so the result is verifiable rather than just magic.
How do I calculate a discount?
Use 'What is X% of Y?' with the discount rate and original price to get the discount amount, then subtract. Or use 'Y decreased by X%' to get the final price directly.
Is it free?
Yes - completely free and unlimited.