Experimental uncertainties should almost always be rounded to one significant figure.
The last significant figure in any stated answer should usually be of the same order of magnitude (same decimal position) as the uncertainty, when written in the same units.
| Incorrect | Correct |
| 8.123456 ± 0.0312 m/s | 8.12 ± 0.03 m/s |
| 3.1234 x 104 ± 2 m | (3.1234 ± 0.0002) x 104 m or 31 234 ± 2 m |
| 5.6789 x 10-7 ± 3 x 10-9 kg | (5.68 ± 0.03) x 10-7 kg |