Significant Figure Rules
Provided by the Academic Center for Excellence 1 Reviewed April 2008
Significant Figure Rules
You can navigate to specific sections of this handout by clicking the links below.
Determining Number of Significant Figures (Sig Figs): pg. 1
Addition/Subtraction: pg. 2
Multiplication/Division: pg. 2
Conversions: pg. 3
Sample Problems: pg. 4
Determining Number of Significant Figures (Sig Figs)
1) All non-zero integers are significant.
Example 1: 412945 has 6 sig figs.
2) All exact numbers have an unlimited number of sig figs.
Example 2: If you counted the number of people in your class to be exactly 35,
then 35 would have an unlimited number of sig figs.
Example 3: It has been determined that exactly 60 seconds are in a minute, so 60
has an unlimited number of sig figs.
3) Zeros are significant depending on what kind of zeros they are.
a. Zeros that are between non-zero integers are always significant.
Example 4: The zeros in 100045, 600.4545, and 23.04 are all significant because
they are between non-zero integers.
b. Zeros that come before non-zero integers are never significant.
Example 5: The zeros in 098, 0.3, and 0.000000000389 are not significant
because they are all in front of non-zero integers.
c. If the zeros come after non-zero integers and are followed by a decimal
point, the zeros are significant.
Example 6: The zeros in 1000. are significant because they are followed by a
decimal point.