Experimental data & uncertainty · SL/HL
Significant Figures Calculator
Enter any decimal or scientific-notation number.
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
Round at the first discarded digit after the requested significant figures.
| Symbol | Meaning |
|---|---|
| significant figures | Digits that communicate the stated precision of a number. |
When to use this calculator
Keep guard digits during calculations and round the final reported result appropriately.
Worked example
The page opens with these example values. The result below is pre-generated for reference.
- Input: 0.004560
- Requested significant figures: 3
- Rounded: 4.56 × 10^-3
- The written input indicates 4 significant figures. Leading zeros are not significant; zeros between significant digits are significant. Trailing zeros in a decimal or scientific-notation mantissa express precision. The first discarded digit determines rounding. Exact halfway cases round away from zero. Adding zeros cannot improve measurement precision.
4.56 × 10^-3
Common mistakes
- Leading zeros are not significant; trailing zeros need context or scientific notation.