Math Calculator
Significant Figures Calculator
Count significant figures, round numbers to a selected number of sig figs, highlight important digits, and convert results into decimal, scientific notation, and E notation.
Leading zeros are not significant
0.00450 = 3 sig figsInteractive Tool
Sig Fig Counter and Rounding Calculator
You can enter whole numbers, decimals, negative numbers, scientific notation, or E notation.
Sig Fig Count
The significant digits are 4, 5, and trailing 0 after the decimal.
Digit Breakdown
Green digits are significant. Muted digits are not counted.
Step-by-Step Explanation
- Ignore leading zeros before the first non-zero digit.
- Count 4, 5, and the final 0 because it is after the decimal point.
- 0.00450 has 3 significant figures.
What Are Significant Figures?
Significant figures, also called sig figs, are the digits in a number that carry useful precision. They are especially important in science, chemistry, physics, engineering, and measurement-based math.
For example, 0.00450 has 3 significant figures because the leading zeros only place the decimal point, while 4, 5, and the final decimal zero show precision.
If you are working with geometry or measurement problems, you may also need the circumference calculator. For incline, ramp, road grade, or rise-over-run problems, try the slope percentage calculator.
How to Use This Significant Figures Calculator
Enter your number
Type a value such as 3500, 35.0056, 0.00450, or 3.5e3.
Choose sig figs
Select how many significant figures you want for the rounded answer.
Read the result
View the sig fig count, highlighted digits, rounded result, scientific notation, and explanation.
Significant Figures Examples
Sig Fig Rules Table
| Rule | Example | Sig Figs |
|---|---|---|
| All non-zero digits are significant | 427 | 3 |
| Leading zeros are not significant | 0.0062 | 2 |
| Zeros between non-zero digits are significant | 1008 | 4 |
| Trailing zeros after decimal are significant | 12.00 | 4 |
| Trailing zeros without decimal can be ambiguous | 3500 | Usually 2 unless specified |
Rounding to Significant Figures
To round a number to significant figures, start counting from the first non-zero digit. Keep the required number of significant digits, then look at the next digit. If the next digit is 5 or more, round up. If it is less than 5, keep the last retained digit unchanged.
3.14159 to 3 sig figs
Keep 3, 1, and 4. The next digit is 1, so the result is 3.14.
0.009876 to 2 sig figs
Ignore leading zeros. Keep 9 and 8. The next digit is 7, so the result is 0.0099.
98765 to 2 sig figs
Keep 9 and 8. The next digit is 7, so the result is 99000.
FAQs About Significant Figures
What does sig fig mean?
Sig fig is short for significant figure. It means a digit that contributes to the precision of a number.
How many significant figures are in 0.00450?
0.00450 has 3 significant figures: 4, 5, and the final 0.
How many significant figures are in 1000?
Without a decimal point or scientific notation, 1000 can be ambiguous. It is often treated as 1 significant figure unless more precision is shown.
Are zeros after a decimal significant?
Yes, trailing zeros after a decimal point are significant. For example, 5.00 has 3 significant figures.
Can this calculator handle scientific notation?
Yes. You can enter values like 3.5e3, 4.20e-5, or normal decimal numbers.