Significant Figures Calculator
Identify the precision of your measurements instantly.
Understanding Significant Figures
Significant figures (often called "sig figs") are the digits in a number that carry meaning contributing to its measurement resolution. In science and engineering, accurately reporting these digits is critical to communicate the precision of equipment and calculations.
- Non-zero digits: Always significant (e.g., 543 has 3).
- Sandwich zeros: Zeros between non-zero digits are significant (e.g., 503 has 3).
- Leading zeros: Never significant; they are just placeholders (e.g., 0.005 has 1).
- Trailing zeros (with decimal): Significant if a decimal point is present (e.g., 5.00 has 3).
- Trailing zeros (no decimal): Generally not significant (e.g., 500 has 1).
Calculation Examples
1. 0.007020: There are 4 significant figures. The leading zeros are placeholders, but the zero between 7 and 2 and the trailing zero after the 2 are significant because of the decimal.
2. 1,200: There are 2 significant figures. Without a decimal point, the trailing zeros are assumed to be placeholders.
3. 1,200.0: There are 5 significant figures. The presence of the decimal makes the trailing zeros significant.
Why Precision Matters
When performing mathematical operations, your final result cannot be more precise than your least precise measurement. If you measure a block as 10.2 cm (3 sig figs) and multiply it by 5.1123 cm (5 sig figs), your answer must be rounded to 3 significant figures to maintain scientific integrity.