Significant Figures Examples Explained

 Examples of Significant Figures in Measurements


When it comes to measurements, significant figures play a crucial role in conveying the precision of a measurement. Significant figures, also known as sig figs, are the digits in a number that carry meaning and contribute to its overall accuracy. Understanding significant figures is essential for scientists, engineers, and anyone working with measurements. Let’s explore some practical examples of significant figures to grasp their importance.

Consider the measurement 3.25 cm. In this case, there are three significant figures: 3, 2, and 5. The leading zeros are not considered significant, as they only indicate the decimal place. Similarly, trailing zeros are not significant unless there is a decimal point. For instance, the measurement 400 m has only one significant figure, while 400.0 m has four significant figures.

Addition and Subtraction with Significant Figures

Performing addition and subtraction with significant figures requires careful attention to detail. The rule is to round the result to the least precise measurement involved in the calculation. Let’s illustrate this with an example.

Suppose we have two measurements: 5.12 g and 3.3 g. To add them, we align the decimal points and calculate the sum: 8.42 g. However, since the least precise measurement has two significant figures, the final result should also have two significant figures. Hence, the sum should be rounded to 8.4 g.

Similarly, for subtraction, we follow the same rule. For instance, if we subtract 0.45 cm from 2.3 cm, we get 1.85 cm. Since the least precise measurement has two significant figures, the result should be rounded to 1.9 cm.

Multiplication and Division with Significant Figures

When it comes to multiplication and division, the rule for determining significant figures is slightly different. In these operations, the result should be rounded to the fewest number of significant figures in the measurement.

Let’s consider an example. Suppose we want to calculate the area of a rectangle with measurements of 3.2 cm and 2.17 cm. Multiplying these values, we get 6.944 cm². However, since the least precise measurement has two significant figures, the result should also have two significant figures. Thus, the area should be rounded to 6.9 cm².

For division, the same rule applies. If we divide 7.5 g by 2.54 cm³, we get 2.9527559 g/cm³. Since the least precise measurement has three significant figures, the result should be rounded to 2.95 g/cm³.

Significant Figures in Scientific Notation

Scientific notation is a useful way to express very large or very small numbers. When working with scientific notation, it is important to consider significant figures.

For example, let’s say we have the number 4.56 x 10^6. In this case, the significant figures are 4, 5, and 6. The power of 10 does not affect the significant figures. Therefore, the number has three significant figures.

Similarly, if we have the number 8.21 x 10^-4, the significant figures are 8, 2, and 1. Again, the power of 10 does not contribute to the significant figures. Thus, the number has three significant figures.

Using a Significant Figure Calculator

To make calculations involving significant figures easier, there are online tools available known as significant figure calculators or sig fig calculators. These calculators allow you to input your measurements and perform calculations while automatically considering the rules of significant figures.

A sig fig calculator eliminates the need for manual rounding and ensures accurate results with the correct number of significant figures. Whether you are performing addition, subtraction, multiplication, or division, using a significant figure calculator can save time and prevent errors in your calculations.

If you want to try a sig fig calculator, visit our website where we provide a user-friendly tool that takes the hassle out of dealing with significant figures.

Practical Examples of Significant Figures in Chemistry Calculations

Significant figures are particularly important in chemistry, where precise measurements are crucial for accurate results. Let’s explore some practical examples of significant figures in chemistry calculations.

Consider a chemical reaction that requires 2.5 moles of a particular substance. In this case, the measurement has two significant figures, and any calculations involving this measurement should be rounded to two significant figures accordingly.

Another example is determining the molar mass of a compound. Suppose we have a compound with a molar mass of 45.678 g/mol. Here, the molar mass has five significant figures. When using this value in calculations, it is important to maintain the appropriate number of significant figures to ensure accuracy.

Rules for Determining Significant Figures

To summarize, here are the rules for determining significant figures:

  1. Non-zero digits are always significant.
  2. Leading zeros (zeros before any non-zero digit) are not significant.
  3. Trailing zeros (zeros after the decimal point) are significant.
  4. Trailing zeros before a non-zero digit (e.g., 400.0) are significant and indicate precision.
  5. Zeros between non-zero digits are significant.

By following these rules, you can ensure that your measurements and calculations have the appropriate number of significant figures, leading to more accurate results.


Significant figures are a vital aspect of measurements and calculations. They provide information about the precision and accuracy of numbers, ensuring that scientific and mathematical data is conveyed correctly. Understanding how to determine significant figures and perform calculations with them is essential for anyone working with measurements in fields such as chemistry, physics, and engineering.

Remember to pay attention to the rules of significant figures, whether you are adding, subtracting, multiplying, dividing, or using scientific notation. And if you want to simplify your calculations, consider using a significant figure calculator. By following these guidelines and using the proper tools, you can confidently work with significant figures and achieve accurate results in your scientific endeavors.

So, why wait? Visit our website and try our sig fig calculator to simplify your significant figure calculations today!

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