Statistics & graphs · SL/HL
Error bar ranges
Find the limits around a mean and label the bar type.
Your values
Number formats & units
Use decimal dots in datasets. Single values also accept decimal commas and scientific notation such as 1.2e-3 or 1.2 × 10⁻³.
Calculated locally. No account or input upload.
Result & working
ExampleThe calculator is loading. The worked example is also shown below.
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Interpretation & assumptions
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Formula & example
The relationship
What the variables mean
| Symbol | Meaning |
|---|---|
| error | The quantity represented by the bar, such as SD or SE. |
Worked example
- Mean / central value
- 12.4
- Error-bar magnitude
- 0.8
- Error type
- SD
- Result unit (optional)
12.4 ± 0.8
Follow the example steps
- lower = mean − error = 12.4 − 0.8 = 11.6
- upper = mean + error = 12.4 + 0.8 = 13.2
Common mistakes
State whether the bars represent SD, SE or another uncertainty.
Incorrect approach
Mean 10, SD 2, n = 4: label ±2 as SE.
Correct approach
SE = 2/√4 = 1; SE bars run from 9 to 11.
More checks before you submit
- Never infer statistical significance solely from whether error bars overlap.
Method notes
This tool formats symmetric bars; it does not decide whether SD, SE or confidence intervals are the right choice.