Scientific Notation Converter

Scientific notation writes a number as a value from 1 to 10 multiplied by a power of 10. So 4,500,000 becomes 4.5 x 10^6, and 0.00045 becomes 4.5 x 10^-4. This converter works both ways. Type a normal number in one box to get E-notation such as 4.5e-4. Type scientific notation in the other box to get the full number back.

E-notation is the short form used by calculators, spreadsheets and code. The "e" means "times 10 to the power of", so 3.5e8 is 3.5 x 10^8. The converter accepts 4.5e-4, 4.5 x 10^-4 or 4.5 * 10^-4. In the standard box, commas, spaces and underscores between digits are ignored, so 1,230,000 works. To convert by hand, move the decimal point until one non-zero digit sits in front of it. Count how many places you moved it. That count is the exponent. Moving left gives a positive exponent, and moving right gives a negative one. So 0.00045 needs four moves to the right to become 4.5, which gives 4.5 x 10^-4.

Two details about precision are worth knowing. Expanding scientific notation back to a standard number is exact, even for exponents up to 1,000. Going the other way, a standard number is read as a regular computer number. That means digits past about the 15th or 16th significant figure can be rounded. For powers of 10 and other exponents, see the Exponent and Power Calculator. To find the exponent of a number, the Logarithm Calculator gives log10 directly.