Percentage Calculator
Calculate percentages
Choose an operation and enter your numbers. Values can represent money, quantities or other consistent units.
Use a decimal point, such as 12.5. Commas group thousands: 35,000 means thirty-five thousand. Enter nonnegative numbers up to 1 trillion; discounts must be 0–100%.
How it works
Example: 15% of 200 = 30.
How it works
Example: 50 out of 200 = 25%.
How it works
Example: From 80 to 100 = 25% increase. The original value must be greater than zero.
How it works
Example: 80 increased by 20% = 96.
How it works
Example: 200 with 15% off = 170; amount saved = 30.
How it works
Example: 80 and 120 have a 40% difference. This is different from percentage change. When both values are zero, this tool displays 0% by convention.
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How to use the percentage calculator
Choose one of the six operations, enter the two values and select Calculate. Use a decimal point, such as 12.5. Commas group thousands: 35,000 means thirty-five thousand. Values can represent prices, quantities or other consistent units; the calculator does not convert currencies.
Inputs must be nonnegative numbers up to 1 trillion. Rates above 100% are allowed for a percentage of a value and increases, but a discount must be between 0% and 100%. This tool does not calculate signed input values, tax rules, compound interest or business net profit.
What is X% of a value?
Divide the percentage by 100 and multiply by the value. For example, 15% of 200 = (15 ÷ 100) × 200 = 30. A percentage above 100% gives more than the original value: 150% of 80 is 120.
What percentage is one value of another?
Divide the part by the total and multiply by 100. For example, 50 out of 200 = (50 ÷ 200) × 100 = 25%. The total cannot be zero. A part greater than the total produces a result above 100%.
Percentage change: increase or decrease
Percentage change = (new value − original value) ÷ original value × 100. A change from 80 to 100 is a 25% increase. A change from 100 to 80 is a 20% decrease. Reversing the direction changes the reference value and therefore the percentage. The original value must be greater than zero.
Apply a percentage increase or discount
For an increase, multiply by 1 + percentage ÷ 100. Increasing 80 by 20% gives 96. For a discount, multiply by 1 − percentage ÷ 100. A 15% discount on 200 gives 170, saving 30.
Adding 20% and then subtracting 20% does not restore the original value: 100 becomes 120 and then 96, because the second percentage uses a different base.
Percentage difference versus percentage change
Percentage difference = absolute difference ÷ average of the two values × 100. For 80 and 120, the difference is 40 and the average is 100, giving 40%. The result is the same when you reverse the two inputs. Percentage change from 80 to 120, by contrast, is 50% because its denominator is the original value, 80.
With two zero inputs, the average-based formula would divide by zero. This calculator displays 0% by convention and explains that choice in the result. With one zero and one positive input, the percentage difference is 200%.
Percentages and percentage points
If a rate rises from 10% to 15%, it increases by 5 percentage points, or 50% relative to its original level. To find the relative change, enter 10 and 15 under Percentage change. Subtract the two rates directly to find percentage points.
Precision, history and language
Calculations use JavaScript numbers without rounding intermediate values. Main results show two decimal places, while the calculation details show up to 12. Displayed values are rounded, and very small results may appear as zero; this is a numerical estimate rather than arbitrary-precision arithmetic.
The calculation runs in your browser. The last 10 calculation summaries are saved in local storage on this device and can remain after you close the page. Use Clear history to remove them, especially on a shared device. The calculator does not submit your input values to our server.
The Portuguese percentage calculator shares the same calculation code, with localized labels, formulas and number formatting. Switching language opens the equivalent page without transferring the current inputs; each language has its own saved history.