0.003456 → 3 sig.
- Input
- 0.003456
- Expected output
- 0.00346
3rd sig is 5; next is 6 → round 5→6.
round to significant figures
Round to Significant Figures
To round 3.456 to 3 sig figs: identify the 3rd significant digit (5), look at the next (6 ≥ 5 → round up) → 3.46.
Significant figure rounding algorithm
- 1. Find the Nth significant figure. 2. Look at the next digit. 3. If ≥ 5, increment the Nth. 4. Replace remaining digits with zeros (or remove if after decimal point).
Examples
15200 → 3 sig.
- Input
- 15200
- Expected output
- 15200 (ou 1.52×10⁴)
3rd sig is 2; next is 0 < 5 → keep.
Full tool FAQ
Significant figures are the digits that carry meaning regarding the precision of a measurement. They include all non-zero digits, sandwiched zeros, trailing zeros after a decimal point and, in some cases, leading zeros after the decimal.
Frequently asked questions
What is the rule for "5 in the middle"?
The standard convention rounds 5 up. Banker rounding rounds to the nearest even digit, but the first is most common in education.
Does this page replace official or professional review?
No. It helps explain the scenario and use the tool more safely, but real decisions should consider official sources, full context and qualified guidance when needed.