Scientific Notation Converter
Convert between ordinary numbers and scientific notation, with significant-digit control and exact expansion for huge and tiny values.
How to Use
- Pick a direction
Number → scientific is the default; switch and paste scientific notation to expand it.
- Enter a value
Ordinary numbers accept decimals and negatives; scientific notation accepts e, ×10^ and *10^ forms.
- Control significant digits
Choose the digit count (or auto) and the mantissa is banker-rounded to that precision, with all four forms shown at once.
FAQ
What is the difference between scientific notation and ordinary numbers?
Scientific notation writes a number as a mantissa between 1 and 10 times an integer power of ten (e.g. 1.5 × 10⁸). It keeps very large and very small numbers concise, makes orders of magnitude easy to compare, and supports significant-digit control. Ordinary notation is for reading; scientific is for calculation and transmission.
Why decimal strings?
JavaScript's Number is a 64-bit float with roughly 15 significant decimal digits of precision. Huge values (10²⁰) and tiny ones (10⁻²⁰) accumulate rounding error through float arithmetic. This tool operates directly on decimal strings, so the expanded form matches the mathematical definition exactly.
What is banker's rounding?
Conventional rounding always rounds up at 5, which biases accumulated statistics. Banker's rounding looks at the preceding digit when the boundary is 5 — odd rounds up, even stays — producing an unbiased result. The tool's significant-digit rounding follows this rule.
Are negatives and decimals supported?
Yes. Negative signs are preserved and pure decimals (e.g. 0.00045) convert correctly to 4.5 × 10⁻⁴. The exponent can be any integer.