Percent Difference Calculator
Calculate the percent difference between two numbers using the standard formula based on their average. Enter both values to compare measurements, analyze variations, or understand how much two quantities differ. This free online Percent Difference Calculator is useful for students, teachers, researchers, professionals, and everyday calculations.
Percent change from A to B: 20.00%. Percent difference treats both values equally, while percent change measures from A.
What is Percent Difference Calculator?
Calculate the percent difference between two numbers with the free Percent Difference Calculator. Compare values using the standard formula based on their average to assess variation between measurements or quantities. Use it for statistics, experiments, reports and everyday numerical comparisons. Percent difference is different from percentage change, so choose the calculation that matches your purpose.
Why use this tool?
- Compare two values when neither one is the starting point, such as two measurements or two prices.
- Uses the standard formula, so swapping the two values gives the same result.
- Also shows the percent change from A to B so you can see both figures.
How to use Percent Difference Calculator
- Step 1. Enter value A and value B.
- Step 2. Read the percent difference shown in the result.
- Step 3. Read the percent change line underneath if you need to measure from the first value.
Common use cases
Important notes
- The formula is the absolute difference divided by the average of the two values, multiplied by 100.
- Percent difference is not the same as percent change. Change measures from the first value, so the result depends on the order.
- If both values are zero, the result is not defined and the tool asks for different numbers.
- The calculation uses absolute values in the average, so the sign of each number does not change the divisor.
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Percent Difference Calculator FAQ
What is the percent difference formula?
Percent difference = |A − B| ÷ ((|A| + |B|) ÷ 2) × 100. For 100 and 120, the difference is 20 and the average is 110, so the result is 18.18%.
What is the difference between percent difference and percent change?
Percent difference compares two values symmetrically, using their average. Percent change measures how much a value moved from a starting value, so going from 100 to 120 is a 20% change but an 18.18% difference.
When should I use percent difference?
Use it when neither value is a reference, for example when comparing two measurements. Use percent change when one value is the original.
Why is my result different from a percent increase?
A percent increase divides by the original value, while percent difference divides by the average of both values.