Scientists must be able to express numbers in a variety of formats including the commonly used scientific notation. In addition, and in particular for experimental scientists, it is imperative that the correct number of significant figures is used when reporting experimentally measured parameters. The calculator below allows you to enter a number in one of three formats (decimal notation, scientific notation, or exponential notation), and will output that number in all three formats. The calculator also determines the number of significant figures for the number provided, or it can use input provided by the user to set the number of significant figures for the number.

A decimal is a number expressed in base-ten numeral system. Examples of decimals are 123, 98.69, −659.821, 10359.659586, and 0.0123456789. A decimal, such as 123, expressed in scientific notation has the following format: 1.23 × 10² (assuming 3 significant figures). 123 expressed in exponential (e) notation has the following format: 1.23e2 (e may also be capitalized, i.e., 1.23E2). A few additional examples are shown in the table below.

For the purpose of using the calculator below, it is straightforward to enter decimals and numbers in exponential notation. They may be entered exactly as they appear. Commas may also be entered as thousand separators. For exponential notation, there should not be a space before or after  e . To enter numbers in scientific notation, use the  x  character (letter x; lower or upper case) or  *  character (asterisk) for the multiplication symbol, and use the  ^  character (caret) to indicate the power to which 10 should be raised. For example, 1.23 × 10² may be entered as 1.23 x 10^2. Spaces do not make a difference, so this is fine as well: 1.23x10^2. The asterisk character may also be used, so this will also work: 1.23 * 10^2.

This calculator also determines the number of significant figures (also referred to as significant digits) for the number entered and, in addition, allows you to specify the number of significant figures for the calculated output numbers. This calculator allows for up to fifteen (15) significant figures. Significant figures signify the precision in a given number and often note the level of precision for an experimentally measured parameter. For example, 12.0236 has six (6) significant figures and, in this case, indicates that the number has precision to the fourth decimal place. For more information about significant figures, see our other calculators: Get and Set the Number of Significant Figures, and Significant Figures Calculator for handling significant figures in simple mathematical operations such as additions, subtractions, multiplications, and divisions.