Sig Fig Calculator - Calculate Significant Figures (2024)

The significant figures calculator converts any number into a new number with the desired amount of sig figs AND solves expressions with sig figs (try doing 3.14 / 7.58 - 3.15). What are the significant figures rules? Those concepts will be explained throughout this page as well as how to use a sig fig calculator.

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Let us guide you on how to put this calculator to the best use:

1. Enter a number or expression.

2. The significant figures calculator will instantly summarize the results, including the number in decimal notation and the number of significant figures in the number (or expression).

3. To reduce this number to a different number of significant figures, provide the desired significant figures in the round to sig fig field.

4. Right away, the number is rounded to the specified significant figures in the results.

For example, consider the number 24.0725. When we enter 24.0725, the significant figures calculator tells us that the number has 6 significant figures. Additionally, it shows us the decimal notation, the scientific notation, 2.40725 × 10¹, and the E-notation, 2.40725e+1.

Suppose we want only 3 significant figures for this number. When we input 3 in the round to sig-fig field, the decimal notation 24.1 is immediately available in the results section.

To determine what numbers are significant and which aren't, use the following rules:

1. The zero to the left of a decimal value less than 1 is not significant.

2. All trailing zeros that are placeholders are not significant.

3. Zeros between non-zero numbers are significant.

4. All non-zero numbers are significant.

5. If a number has more numbers than the desired number of significant digits, the number is rounded. For example, 432,500 is 433,000 to 3 significant digits (using half up (regular) rounding).

   See Also

   Significant Figures Calculator & Counter (Sig Fig Calculator)

6. Zeros at the end of numbers that are not significant but are not removed, as removing them would affect the value of the number. In the above example, we cannot remove 000 in 433,000 unless changing the number into scientific notation.

• For addition and subtraction operations, the result should have no more decimal places than the number in the operation with the least precision. For example, when performing the operation 128.1 + 1.72 + 0.457, the value with the least number of decimal places (1) is 128.1. Hence, the result must have one decimal place as well: 128.̲1 + 1.7̲2 + 0.45̲7 = 130.̲277 = 130.̲3. The position of the last significant number is indicated by underlining it.

• For multiplication and division operations, the result should have no more significant figures than the number in the operation with the least number of significant figures. For example, when performing the operation 4.321 × 3.14, the value with the least significant figures (3) is 3.14. So the result must also be given to three significant figures: 4.32̲1 × 3.1̲4 = 13.̲56974 = 13.̲6.

• If performing addition and subtraction only, it is sufficient to do all calculations at once and apply the significant figures rules to the final result.

• If performing multiplication and division only, it is sufficient to do all calculations at once and apply the significant figures rules to the final result.

• If, however, you do mixed calculations – addition/subtraction and multiplication/division – you need to note the number of significant figures for each step of the calculation. For example, for the calculation 12.1̲3 + 1.7̲2 × 3.̲4, after the first step, you will obtain the following result: 12.1̲3 + 5.̲848. Now, note that the result of the multiplication operation is accurate to 2 significant figures and, more importantly, one decimal place. You shouldn't round the intermediate result and only apply the significant digit rules to the final result. So for this example, the final steps of the calculation are 12.1̲3 + 5.̲848 = 17.̲978 = 18.̲0.

• Exact values, including defined numbers such as conversion factors and 'pure' numbers, don't affect the accuracy of the calculation. They can be treated as if they had an infinite number of significant figures. For example, when using the speed conversion, you need to multiply the value in m/s by 3.6 if you want to obtain the value in km/h. The number of significant figures is still determined by the accuracy of the initial speed value in m/s – for example, 15.23 × 3.6 = 54.83.

Daniel, our experienced programmer, and Steve, our in-house physicist and expert in creating appealing scientific content, have been around since the early days of Omni Calculator. They conceived the idea for a significant figures calculator when discussing floating point integers in various programming languages and what it means in the real world.

Now, they use this tool frequently to ensure they're using the minimum number of digits after the decimal point in their calculations. More than anything, they're happy to share this tool with everyone who needs it.

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