Online Tool Store
Percentage Calculator
Calculate percentages, percentage change, percentage difference, increases, decreases, parts, and totals for free. Everything runs in your browser.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Example shown - choose a question and replace the numbers with your own.
What is 15% of 240?
Answer
How the percentage calculator works
- Choose the plain-language question that matches the problem you have.
- Replace the example values with your numbers; the answer updates as you type.
- Read the result as a sentence, then use the formula underneath to check the method.
The percentage formulas
Percent means per hundred. The calculator rearranges the relationship between a part, a whole, and a percentage depending on which value is missing.
Part = whole x percent / 100
Percent = part / whole x 100
Whole = part / percent x 100
Change % = (new - old) / |old| x 100
For the example shown, 15% of 240 is 240 x 15 / 100 = 36. Percentage difference uses the absolute difference divided by the average magnitude of the two values, while an increase or decrease multiplies the starting value by 1 plus or minus the percent as a decimal.
FAQ
What is the difference between percentage change and percentage difference?
Percentage change compares a new value with a starting value, so direction matters and the starting value is the denominator. Percentage difference compares two values without treating either as the starting point, so it divides their absolute difference by their average.
Can a percentage be greater than 100%?
Yes. A percentage above 100% represents more than the reference amount. For example, 150% of 40 is 60, and an increase from 40 to 100 is 150%.
Why can I not calculate percentage change from zero?
Percentage change divides the change by the starting value. When that starting value is zero, the calculation would require division by zero, so no finite percentage change exists.
How are long decimal answers rounded?
The calculator keeps full JavaScript number precision while calculating and displays up to 10 decimal places. This keeps everyday answers readable without rounding intermediate steps.
Are my numbers sent to a server?
No. Every calculation runs locally in your browser. The values you enter are not uploaded, stored, or sent to a calculation service.
How we compare
| Feature | Online Tool Store | Calculator.net | Omni Calculator | RapidTables |
|---|---|---|---|---|
| Find a part, percent, or whole | Yes | Yes | Yes | Yes |
| Increase or decrease a value | Included | Included | Included | Not in main form |
| Percentage change | Included | Included | Separate calculator | Included |
| Percentage difference | Included | Included | Separate calculator | Not in main form |
| Shows the formula with your numbers | Yes, instantly | Formula examples | Live formula | Formula examples |
Calculator.net, Omni Calculator, and RapidTables all handle core percentage questions. Choose this Percentage Calculator when you want the common problem types in one focused tool, written as familiar questions with the calculation shown using your own numbers.