Experimental data & uncertainty · SL/HL
Percentage Change & Difference Calculator
Choose the comparison that matches the question.
Your values
Start with the example or enter your own values. Use a dot for decimals and e for scientific notation.
Calculated locally. No account or input upload.
Result & working
ExampleThe calculator is loading. The worked example is also shown below.
Step-by-step working
The formula
percentage change = (new − initial)/|initial| × 100%
percentage difference = |A−B| / [(|A|+|B|)/2] × 100%
| Symbol | Meaning |
|---|---|
| change | Directional change relative to an initial value. |
| difference | Symmetric comparison when neither value is the accepted baseline. |
When to use this calculator
Read the wording carefully: “change” and “difference” have different denominators.
Worked example
The page opens with these example values. The result below is pre-generated for reference.
- percentage change = (new − initial)/|initial| × 100
- = (125 − (100))/|100| × 100 = 25%
25%
Common mistakes
- Percentage change is undefined when the initial value is zero.