Quick guide
How to use this calculator
- Enter a nonzero or zero finite decimal.
- Choose the significant-figure count.
- Use the explicit notation to see retained trailing zeros, including zero's stated precision.
Calculation method
Precision follows the first nonzero digit
The first nonzero digit establishes the leading power of ten. The calculator keeps the requested count from there and applies half-even at the next digit.
Worked example
Three significant figures
The first three significant digits of 12,345 are 1, 2, and 3; the following 4 does not raise them.
12,345 → 1.23 × 10⁴
Supported inputs
Precision and limits
Exact decimal input
Finite decimals use integer-scaled arithmetic, with no binary floating-point conversion.
Input boundary
Unless stated otherwise, use at most 200 digits total and 100 digits after the decimal marker.