Quick guide
How to use this calculator
- Enter two written values; use a decimal marker or scientific notation to clarify trailing zeros.
- Choose +, −, ×, or ÷.
- Compare the exact intermediate with the conventionally reported value.
Calculation method
Reporting rules depend on the operation
Addition and subtraction retain the coarser last-significant place. Multiplication and division retain the smaller significant-figure count. Half-even resolves an exact rounding tie.
Worked example
Multiplication with stated precision
12.30 has four significant figures and 4.5 has two, so the exact product 55.35 is reported with two significant figures.
12.30 × 4.5 = 55.35 → 55
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.
Not uncertainty analysis
These are written-digit reporting conventions; they do not estimate experimental uncertainty.