Percentage Calculator
Work out percentages, percentage change and 'X is what percent of Y'.
Percentage Calculator
This tool runs entirely in your browser. Your files never leave your device.
How to use
- 1Choose the type of calculation with the tabs.
- 2Enter your two numbers.
- 3The result updates automatically.
About this tool
The Percentage Calculator handles the three most common percentage questions: finding a percentage of a number, expressing one number as a percentage of another, and calculating the percentage increase or decrease between two values. These come up constantly in everyday situations — working out a restaurant tip, checking how much a 'X% off' sale actually saves, comparing this month's numbers to last month's, or converting a raw score into a percentage. Switch between the three modes with the tabs above; each one only asks for the two numbers it actually needs, and the result updates as you type, so there's no separate 'calculate' button to press.
Benefits & use cases
- Work out a tip, sales tax or discount while shopping or eating out.
- Check how much a 'X% off' sale price actually saves in real money.
- Compare month-to-month or year-to-year change in revenue, weight or any other figure.
- Convert a raw score, like 42 out of 50, into a percentage for grading.
- Verify a percentage quoted in a report, invoice or news article.
Frequently asked questions
How is percentage change calculated?
Percentage change is (new − old) ÷ |old| × 100. A negative result is a decrease.
Does this store my numbers?
No. The calculation runs entirely in your browser.
Why do I get a negative number for percentage change?
A negative result means the value decreased — for example, going from 80 to 60 is a change of −25%. A positive result means an increase.
Can I calculate a percentage of a percentage (compounding)?
Not directly — this tool handles one calculation at a time. To compound, take the result of the first calculation and use it as the starting value in a second calculation.