Which mode should I use for old value to new value?
Use percent change. It compares the movement from the old value to the new value using the old value as the baseline.
Percent Calculator
Calculate percent-of values, percent change, percent difference, and reverse percentages with visible formulas for discounts, markups, before-and-after values, and original-price reconstruction.
Pick the baseline before you type
Most percentage mistakes come from choosing the wrong baseline. This calculator separates percent-of, directional change, symmetric difference, and reverse percentage questions so the denominator matches the question.
Pick the right percentage question
- Use percent of for questions like: What is 18% of 240?
- Use percent change for questions like: What percent did 80 change to 92?
- Use percent difference for questions like: How different are 48 and 60?
- Use reverse percent for questions like: What was the original price before 25% off?
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Core percentage formulas
Each mode answers a different denominator question.
Percent of
Percent change
Percent difference
Reverse increase
Reverse decrease
When results get misread
- A zero starting value makes percent change undefined.
- Percent difference is symmetric; percent change is directional.
- A 20% discount followed by a 20% increase does not return to the original value.
- Reverse percentage divides by the change multiplier instead of applying the percent again.
FAQ
Why is percent difference different from percent change?
Percent difference compares two values against their average, so the result is the same whichever value is entered first.
