Experimental data & uncertainty · SL/HL
Percentage Error & Difference Calculator
Choose the comparison that matches the question; the three denominators answer different questions.
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
error = |experimental − accepted|/|accepted| × 100%
difference = |a − b|/[(|a|+|b|)/2] × 100%
change = (new − initial)/|initial| × 100%
| Symbol | Meaning |
|---|---|
| accepted | Reference used for percentage error. |
When to use this calculator
Percentage error uses a reference value; percentage difference is symmetric when neither value is privileged.
Worked example
The page opens with these example values. The result below is pre-generated for reference.
- Percentage error = |experimental − accepted|/|accepted| × 100
- = |9.7 − (9.81)|/|9.81| × 100 = 1.121305%
1.121305%
Common mistakes
- Do not swap error and difference just because both return a percentage.