What is Signficant Figure Calculator?

Sig Fig Calculator is a basic tool to do calculations on expressions and find significant figures. You can find the sig fig of a number using this calculator.

How to use?

1. Enter your expression or number.
2. Click calculate button
3. This tool will show you step by step instruction on how it arrived at the significant numbers.

What are Significant Figures

Significant Figures is a method of rounding off numbers by only showing the most valuable numbers in a big number. It is used to make the process of calculation easier, like for example, it is easier for our brains to comprehend five million dollars than an exact number. This is why sometimes the numbers are rounded off as accuracy is not always important. Signficant figures is a scientific method to proceduraly do this rounding off based on a methodogical way.

Sometimes, numbers can show false precision by showing insignificant numbers, like if the number is 526.02000, while the equipment measuring it can atmost measure till 526.02. The last three zeros make it seem like it is a very accurate number while it acutally isn't. This problem is solved by using significant figures. You can read more here in this wikipedia article - Significant Figures - Wikipedia

Rules for determining Significant Figures

Rule 1: Non-zero numbers are always significant.

For example, 68.35 has four significant figures and 3.21 has three significant digits.

Rule 2: Any zeros between two significant digits are significant.

For example, 602 has three significant figures. You cannot remove the 0 from there.

Rule 3: In numbers with decimal portion, the trailing zeros are significant.

For example, in case of 0.00520, the last zero is significant. Infact, all zeros in it are significant. This is to show maximum precision.

Rule 3: Leading zeros are never significant.

For example, in case of 0.0000026, there are only two significant figures, whicha re 2 and 6.

Rounding of Significant Figures

Rounding is done as a general method to make it easier to read the value, like rounding off to n digits. It is also a way to not show the probability of error. The number of people living in a town is 45,000 but it may have an error in the range of thousands, while the number of people living in a country is 45,000,000 and in this case the error maybe upto a million. Both have two significant numbers but the error margin is different.