Percentage Difference Calculator
Use this when neither value is the “correct” one — two quotes, two measurements, two suppliers. The result is the same whichever order you type them in, because the comparison is made against the average of the two values.
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How it works
- Find the absolute difference between the two values.
- Find the average of the two values.
- Divide the difference by the average and multiply by 100.
See it in action
Worked examples
Compare 50 and 75
- Absolute difference: |50 − 75| = 25
- Average: (50 + 75) ÷ 2 = 62.5
- Divide and ×100: 25 ÷ 62.5 × 100 = 40%
Answer: 40% difference
Comparing two peer measurements with no clear baseline — two test scores, two quotes, two sensor readings.
Compare 100 and 150
- Absolute difference: |100 − 150| = 50
- Average: (100 + 150) ÷ 2 = 125
- Divide and ×100: 50 ÷ 125 × 100 = 40%
Answer: 40% difference
Symmetric comparison of two options where neither is the “original” — e.g. two supplier prices.
Compare 200 and 250
- Absolute difference: |200 − 250| = 50
- Average: (200 + 250) ÷ 2 = 225
- Divide and ×100: 50 ÷ 225 × 100 = 22.22%
Answer: 22.22% difference
Comparing two close values where the average denominator keeps the result symmetric and fair.
Compare 1,000 and 1,500
- Absolute difference: |1,000 − 1,500| = 500
- Average: (1,000 + 1,500) ÷ 2 = 1,250
- Divide and ×100: 500 ÷ 1,250 × 100 = 40%
Answer: 40% difference
Comparing two large peer figures — two factory outputs, two city populations — without picking a base.
Answers
Frequently asked questions
When should I use percentage difference instead of percentage change?
Use difference when the two values are peers with no clear baseline. Use change when one value came before the other.
Why is 40 vs 60 a 40% difference and not 50%?
Percentage difference divides by the average (50), not by one of the values. 60 is 50% more than 40, but the symmetric difference is 40%.
Can the result exceed 100%?
Yes, up to 200% when one value is zero and the other is not.
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