Scientific notation converter
Turn any number into scientific notation (standard form), engineering
notation and E-notation at the same time, round it to a chosen number of
significant figures, and see exactly how the conversion was done. It is
built for science homework, physics and chemistry calculations, electronics,
and anyone who has to read or write very large or very small numbers without
miscounting zeros. A figure like 149,600,000 becomes 1.496 × 10⁸, and a tiny
value like 0.00042 becomes 4.2 × 10⁻⁴.
The input box is deliberately forgiving: paste a plain decimal, type
E-notation such as 1.496e8, or even a fully formatted 4.2 × 10⁻⁴, and the
converter parses all of them. Commas and stray spaces used as digit groupers
are stripped, so 1,496,000 and 1496000 are treated identically.
How it works
Scientific notation writes a value as a mantissa whose absolute value lies
between 1 and 10, multiplied by a power of ten. To convert a decimal the tool
finds the exponent as the floor of log₁₀(|value|), then divides to get the
mantissa:
exponent = floor(log₁₀|value|) and mantissa = value ÷ 10^exponent
Engineering notation uses the same value but forces the exponent to the
nearest lower multiple of three, so it maps directly onto SI prefixes. That is
why the tool also names the matching prefix — 10³ is kilo, 10⁻⁶ is micro,
10⁹ is giga, and so on, all the way out to quetta and quecto.
When you pick a fixed number of significant figures, the mantissa is rounded with the standard rule: keep digits starting from the first non-zero digit and round the last kept digit. Choosing full precision keeps every digit the IEEE-754 double can hold (about 15 to 17 significant digits).
Worked example
Take Avogadro’s number of particles in a sample, written sloppily as
602214000000000000000000. Enter it and the converter reports:
- Scientific notation:
6.02214 × 10²³ - Engineering notation:
602.214 × 10²¹ - E-notation:
6.02214e+23
Set the significant-figures control to 3 and the mantissa rounds to
6.02, giving 6.02 × 10²³. The working panel shows each step: the parsed
value, the exponent from floor(log₁₀|value|), the mantissa after dividing by
10²³, and the engineering re-bucketing to an exponent of 21.
Quick reference
| Decimal | Scientific | Engineering | SI prefix |
|---|---|---|---|
| 149,600,000 | 1.496 × 10⁸ | 149.6 × 10⁶ | mega (M) |
| 0.00042 | 4.2 × 10⁻⁴ | 420 × 10⁻⁶ | micro (µ) |
| 47,000 | 4.7 × 10⁴ | 47 × 10³ | kilo (k) |
| 6.022 × 10²³ | 6.022 × 10²³ | 602.2 × 10²¹ | zetta (Z) |
Type your value, choose how many significant figures you want, and read every form at once — entirely in your browser, with nothing uploaded.