Significant Figures ↔ Uncertainty Estimator

Significant figures are shorthand for uncertainty: each extra digit roughly cuts the relative uncertainty tenfold. This tool converts between a sig-fig count and the rule-of-thumb relative uncertainty (±0.5 in the last digit) — useful when judging whether a result is meaningful.

How to interpret the result

Worked check: 3 significant figures → 50/10² = 0.50% relative uncertainty (e.g. 1.00 ± 0.005). Four figures → 0.050%. This is an estimate, not a substitute for proper error propagation.

Assumptions

• Rule-of-thumb: ±0.5 in the last reported digit
• Not a replacement for formal uncertainty analysis