What are the Rules of Significant Figures in Physics?

What are the rules of significant figures in physics?

There are some terms that are quite common in both physics and mathematics so, significant figures are one of those terms.

If we explain significant figures in simple words then we can say that significant figures are the non-zero values.

But it is not over here, there are some rules of significant figures either it is regarding physics or mathematics.

And we will surely discuss all of these rules of significant figures below. After having a look at these rules, you must be clear about the concepts of significant figures.

So, let’s get started.

What are significant figures?

As we have mentioned above that non-zero values are known as significant figures but it doesn’t mean a significant figure doesn’t contain any zero.

We can say that a significant figure must be started from a non-zero digit but it can contain any zero in the middle of the value.

Understanding the proper concept of the significant figures, we need to go through the rule of significant figures.

And we are going to discuss them in detail below.

3 rules of determining significant figures

There are majorly three rules of determining the significant figures in a value and these three general rules are discussed below.

1.      Non-zero digits are significant

It is quite obvious that non-zero numbers are always significant like a value containing the following numbers 12345, all of these are significant.

The simple is that if a value starts from the non-zero number, it can be considered as a significant figure.

2.      Zero between two significant zeros are significant

As we have mentioned above that it doesn’t mean that a significant figure doesn’t contain any zero so, let’s have a look.

If there is a value containing zero in the middle like the supposed value is 123067 then the 0 between 3 and 7 is also significant.

3.      Trailing zeros in a decimal number is significant

We can say that this rule is only applicable on the decimal numbers and trailing zeros are also known as final zeros.

If a value has an ending digit zero and the value is considered as the decimal point number then the ending zero is also termed as significant.

How to determine significant figures?

There are two major methods of determining significant figures; one is to follow the above-mentioned rules and secondly, you can use an online tool for this.

Fortunately, you can search any significant figures calculator online, they are specifically designed to determine significant figures.

Sig fig calculators are very simple to use same as the other tools or calculators, all you need is to enter some values and after submitting, you’ll get the answer.

So, you can go for both of the approaches as both of them are useful and effective but online calculators are somehow a level-up game.

And that’s why it deserves to be discussed in detail and we are going to do it below.

What are sig fig calculators?

Same as the other calculators, using sig fig calculator is very simple like you need to enter a number or expression.

Then you need to enter a round value and the range of numbers is from 0 to 100. We can say that the working of every sig fig calculator is the same.

Most of the calculators are free of cost and all you need to do is search for a calculator, pick a suitable one for you, enter the value and then get the desired results.

How to use a sig fig calculator?

As we have mentioned above that the working of all of the sig fig calculators is almost the same and that’s why we have shortlisted the general steps.

And the shortlisted steps are discussed below, you can have an eye on them.

  • Search for a sig fig calculator
  • Enter a number
  • Select a round value that must be between 0 to 100
  • Click on the “calculate” or “submit” button
  • You’ll get the answer

We are sure that you are pretty clear about significant figures and how to find them using an online calculator.


There are many terms that are considered as important either it is related to physics or mathematics and significant figures are also considered as important.

We have shared the general rules of determining the significant figures and these rules must be very helpful.

And we have also discussed that how you can find significant figures using an online calculator and the working of the sig fig calculator.

The good thing is an online calculator designed to find significant figures also works on the rules that are discussed above.

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About the Author: Barry Lachey

Barry Lachey is a Professional Editor at Zobuz. Previously He has also worked for Moxly Sports and Network Resources "Joe Joe." he is a graduate of the Kings College at the University of Thames Valley London. You can reach Barry via email or by phone.