Overview
Type or paste a measurement to see its significant-figure interpretation, scientific notation, and rounded outputs. The calculator understands 0.004560, 1200., and 1.200e3, keeps trailing zeros where appropriate, and highlights each decision in the steps log.
Switch to Round, Operations, or Batch mode to apply tie-breaking rules (half-up, half-even, away-from-zero), compare textbook versus final rounding, or process a whole list of numbers and expressions. Every action is reflected in the shareable URL so you can bookmark or send a working log.
Count reveals the sig-fig interpretation of a single number, Round controls significant or decimal rounding with tie rules, Operations evaluates + − × ÷ expressions with textbook vs final rounding, and Batch processes line-by-line inputs or CSV-style rows.
Result
How it’s calculated
FAQ
How are significant figures counted?
Leading zeros are ignored, trailing zeros only count when a decimal point or scientific notation is present, and numbers like 1200. or 1.200e3 retain their intended precision.
What is the difference between textbook and final-only modes?
Textbook mode rounds after each intermediate operation so students can see classroom-style precision loss, while final-only mode keeps full precision until the last step before applying the same tie-breaking rule.