Significant Figures Calculator – Rules, Examples, and Guide

Your resource hub for learning significant figures with examples and calculation tips.

Why Significant Figures Matter

Significant figures, often called sig figs, are essential in science, engineering, and mathematics. They make sure results are expressed with the correct precision, preventing false accuracy and misinterpretation.

Core Rules of Significant Figures

1. Non-zero digits

All non-zero digits are always significant. Example: 123 has three sig figs.

2. Leading zeros

Zeros before non-zero digits are not significant. Example: 0.0045 has two sig figs.

3. Captive zeros

Zeros between non-zero digits are significant. Example: 1002 has four sig figs.

4. Trailing zeros

Zeros after a decimal are significant. Example: 45.00 has four sig figs.

Applying Rules in Calculations

Addition & Subtraction

Round to the least number of decimal places among the numbers.

Example: 12.3 + 1.45 = 13.75 → round to one decimal → 13.8.

Multiplication & Division

Round to the least number of significant figures among the numbers.

Example: 2.15 × 3.4 = 7.31 → least sig figs is 2 → 7.3.

Use the Online Calculator

Learning the rules is important, but solving by hand can be slow. For fast and accurate results, try the Significant Figures Calculator. It applies all the rules instantly and shows you the correct rounded answer.

Connect With Us

Follow updates and resources on our Facebook page.