Convert any number to scientific notation and back, with the mantissa and exponent explained.
Or type a notation value below, for example 1.23e4, to convert it back to an ordinary number.
Scientific notation writes a number as a × 10^b, where a is between 1 and 10. It is how science handles very large and very small numbers without pages of zeros.
scientific notation
How to use this tool
Type any ordinary number, for example 12300 or 0.00045.
The result is split into a (between 1 and 10) and the power of 10.
Type a value like 1.23e4 in the second box to get the ordinary number.
The engineering form groups the exponent in threes, matching SI prefixes like kilo and milli.
Formula & worked example
12,300 = 1.23 × 10^4, because 1.23 × 10,000 = 12,300. And 0.00045 = 4.5 × 10^−4.
Limitations — read this before you rely on it
Scientific notation is exact in principle, but computers store decimals in binary, so extremely large or tiny values may show tiny rounding in the last digits. Trailing zeros that carry measurement precision are not preserved by a plain number input.
Frequently asked questions
A compact way to write very large or small numbers as a number between 1 and 10 times a power of 10, for example 1.23 × 10^4.
Move the decimal point until one digit is left before it: 1.23, counting 4 moves, gives 1.23 × 10^4.
Move the decimal right: 4.5 with 4 moves right gives a negative exponent, 4.5 × 10^−4.
The same idea, but the exponent is always a multiple of 3, matching kilo (10^3), milli (10^−3) and so on.
Yes: 1.23e4 in calculators and code means 1.23 × 10^4.