Frequently Asked Questions

Significant figures (also called significant digits) are the meaningful digits in a number that indicate the precision of a measurement or calculation. They tell us how accurately we know a value and help prevent false precision in scientific calculations.

For example, if you measure something as 12.3 cm, you have 3 significant figures, indicating you know the value to the nearest 0.1 cm.

0.00456 has 3 significant figures.

The leading zeros (0.00) are not significant - they only indicate the position of the decimal point. Only the digits 4, 5, and 6 are significant because they are non-zero digits.

You can verify this using our calculator's step-by-step mode to see exactly how each digit is analyzed.

1200 has 2 significant figures.

The trailing zeros in whole numbers (without a decimal point) are ambiguous and typically not considered significant. Only the digits 1 and 2 are clearly significant.

However, 1200. has 4 significant figures because the decimal point indicates that the trailing zeros are meaningful and show precision.

To avoid ambiguity, use scientific notation: 1.2 × 10³ (2 sig figs) or 1.200 × 10³ (4 sig figs).

To round to 3 significant figures:

1. Identify the first 3 significant digits in your number
2. Look at the digit immediately after the 3rd significant digit
3. Apply rounding rules:
   • If the digit is less than 5: round down
   • If the digit is 5 or greater: round up

Examples:

• 1.2367 → 1.24 (rounded up because 6 > 5)
• 1.2343 → 1.23 (rounded down because 4 < 5)
• 0.004567 → 0.00457 (rounded up because 6 > 5)

Using our calculator is simple:

1. Enter your number: Type any number, decimal, fraction, or scientific notation
2. Choose mode: Select Basic, Advanced, or Batch mode
3. Set options: Enable rounding, step-by-step analysis, or other features as needed
4. View results: See instant analysis with sig figs count, scientific notation, and more
5. Copy or share: Use the built-in copy and share functions

For detailed instructions, visit our How to Use page.