Online Tool Store
Percentage Calculator
Calculate percentages, percentage change, percentage difference, increases, decreases, parts, and totals for free. Everything runs in your browser.
This works right here on your device — nothing gets sent out.
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.
- Pick how many decimal places you want, and use Copy result to take the answer and its formula with you.
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
Original = final / (1 +/- percent / 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.
How do I find the original value before a percentage increase or decrease?
Choose the original-value question, enter the final value and the percentage, and pick increase or decrease. The calculator divides the final value by 1 plus (or minus) the percentage as a decimal. For example, 115 after a 15% increase was 115 / 1.15 = 100.
How do I calculate a percentage of a number?
Divide the percentage by 100 and multiply by the number. For example, 15% of 240 is 15 / 100 x 240 = 36.
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 | Pearson | GigaCalculator |
|---|---|---|---|---|
| Percentage change and percentage difference | Yes | Yes | Change listed; difference not listed | Yes |
| Find the original value before a percentage change | Yes | Not listed | Yes | Not listed |
| Copy the result | Yes | Not listed | Yes | Not listed |
| Choose decimal places | Yes | Not listed | Friendly or more digits | Not listed |
| Shows the calculation | Live, with your numbers | Formula examples | Step-by-step | Worked examples |
Calculator.net, Pearson, and GigaCalculator all handle core percentage questions. Choose this Percentage Calculator when you want the common problem types plus finding the original value, a decimal-places setting, and a copyable result in one focused tool, with the calculation shown using your own numbers.