Significant Figures Calculator

Number :
Significant figures :
Least significant decimal :

Always display scientific notation.

This calculator counts significant digits in any number. You may use the number that you want to have formatted with significant figures and this calculator will display the formatted version.

This calculator rounds in scientific way, it rounds up if the next digit is greater than 5, down if less than 5. Any embedded or any non-zero digit or trailing zero is considered as a significant figure. When the figure is leading with zeros are not the significant, in this case the number may be padded with zero or rounded to make the number as significant figures.

Significant Figures Rules



All the reliable digits and first uncertain digit in the result of a measurement are called significant digits or significant figures.

Example: If the length is measured, as 15.6 cm the digits 1 and 5 are reliable or certain where as 6 is uncertain or doubtful digit, so the measurement has 3 significant figures.

General rules for determining the number of significant figures:

  1. All the non-zero digits are significant.
    • Example : 6543 has 4 significant figures.
  2. All zeros occurring in between the two non-zero digits are sig.
    • Example: 6003 has 4 significant figures.
  3. In a number without decimal zeros on the right of non-zero digits are not sig.
    • Example : 6300 has 2 significant figures.
  4. In a number with decimal, zeros on the right of the last no zero digits are sig.
    • Example : 1.34000 has 6 significant figures.
  5. In a value less than 1, zeros occurring between the decimal point and non-zero digits on the right or not significant figures.
    • Example : 0.0037 has 2 significant figures.
  6. The change in unit of measurement of quantity does not affect the number of significant figures. When some value is expressed in an exponent form the exponent does not affect the number of significant figures.
    • Example: 23 * 10 4 has 2 significant figures.
    • Example: 23 * 10 –4 has 2 significant figures.

Significant Figures Rules for Arithmetic Operations

Rules for division and multiplication :
In division or multiplication, the final result should retain as many significant figures, as the original number involved that has the least number of significant figures.

For example: ( 22.1 × 1.344 ) ÷ 1.5 = 19.8016

In the above example, the number with the least number of significant figures is 1.5 (2 significant figures). The result should be rounded to 20 (2 significant figures).

Significant figures rules for addition and subtraction :

In addition or subtraction, the final result should retain as many decimal places as the number with the least decimal places.

For example: 30.15 + 3.1 + 10.344 = 43.594

In the above example, the number with the least decimal places is 3.1 (1 decimal place), therefore your result should be rounded to 43.6 (3 significant figures).

Use our free Significant figures calculator to calculate the figures.