Free Online Calculator Tool

Significant Figures Calculator

A precise tool for calculating significant figures in any number. Use it to determine digit count, apply rounding rules, and ensure accuracy in scientific and mathematical measurements.

Significant Figures Counter

Enter any number, decimal, or scientific notation (e.g. 1.23e-4) to count its significant figures.

Total Significant Figures5

Applied Rules

  • Leading zeros are NEVER significant.
  • All non-zero digits and any zeros between them are significant.
  • Trailing zeros to the right of the decimal point ARE significant.

Rules for Significant Figures

Determining which numbers are significant depends on a few fundamental rules:

  • Non-zero digits are ALWAYS significant. (e.g., 123 has 3 sig figs).
  • Sandwiched zeros (zeros between non-zero digits) are ALWAYS significant. (e.g., 1005 has 4 sig figs).
  • Leading zeros are NEVER significant. They only serve as placeholders. (e.g., 0.002 has 1 sig fig).
  • Trailing zeros are ONLY significant if there is a decimal point in the number. (e.g., 100 has 1 sig fig, but 100.0 has 4 sig figs).