Math & Algebra Tool

Significant Figures Calculator

Count significant figures in a number.

Σ The Formula

Count non-zero digits and zeros between/after them

Real World Examples

Non-zeros
123.45 → 5 sig figs
Leading Zeros
0.00456 → 3 sig figs (zeros don't count)
Captive Zeros
1002 → 4 sig figs (zeros count)
Trailing Zeros
2.00 → 3 sig figs (zeros count if decimal present)

# About This Calculator

Significant Figures (or sig figs) are the digits in a number that contribute to its measurement resolution. They include all non-zero numbers, zeros between non-zero numbers, and trailing zeros (only if there is a decimal point).

Leading zeros (0.005) are never significant—they just place the decimal point.

Scientists and engineers use sig figs to track the precision of their instruments. You cannot report a result more precise than your least precise measurement.

This tool instantly counts the significant figures in any number and explains the reasoning.

How To Use

  1. Enter a number (e.g., 0.0450).
  2. Click Count Sig Figs.
  3. The result will show the count.

Frequently Asked Questions

Do leading zeros count?+

No. In 0.0052, there are only 2 significant figures (5 and 2).

Do trailing zeros count?+

It depends! If there is a decimal point (100.), they count (3 sig figs). If not (100), it's ambiguous but usually 1 sig fig.

What about exact numbers?+

Exact numbers (like '3 apples' or '100 cm in a meter') have infinite significant figures because there is no uncertainty.

How many sig figs in 1.40 × 10^5?+

3. Scientific notation makes it clear: only the digits in the coefficient (1.40) are significant.

Why does 0.0 not have 2 sig figs?+

0.0 has 2 significant characters but effectively represents '0'. The rules say leading zeros don't count, but trailing zero after decimal does... actually 0.0 implies 2 sig figs of precision around zero!

Is Significant Figures Calculator free to use?+

Yes, Significant Figures Calculator on Matheric is completely free to use. We believe in accessible education and utility for everyone.

About

Significant Figures (or sig figs) are the digits in a number that contribute to its measurement resolution. They include all non-zero numbers, zeros between non-zero numbers, and trailing zeros (only if there is a decimal point).

Leading zeros (0.005) are never significant—they just place the decimal point.

Scientists and engineers use sig figs to track the precision of their instruments. You cannot report a result more precise than your least precise measurement.

This tool instantly counts the significant figures in any number and explains the reasoning.

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