Convert any number between standard, scientific (mantissa × 10ⁿ), engineering (exponent is a multiple of 3), SI-prefix (k, M, G, …, m, μ, n, …), and E-notation (1.23e4). Decimal arithmetic is done on the string representation so values like 0.1 + 0.2 stay exact.
| Prefix | Symbol | Factor | Name |
|---|---|---|---|
| quetta | Q | 10³⁰ | nonillion |
| ronna | R | 10²⁷ | octillion |
| yotta | Y | 10²⁴ | septillion |
| zetta | Z | 10²¹ | sextillion |
| exa | E | 10¹⁸ | quintillion |
| peta | P | 10¹⁵ | quadrillion |
| tera | T | 10¹² | trillion |
| giga | G | 10⁹ | billion |
| mega | M | 10⁶ | million |
| kilo | k | 10³ | thousand |
| milli | m | 10⁻³ | thousandth |
| micro | μ (u) | 10⁻⁶ | millionth |
| nano | n | 10⁻⁹ | billionth |
| pico | p | 10⁻¹² | trillionth |
| femto | f | 10⁻¹⁵ | quadrillionth |
| atto | a | 10⁻¹⁸ | quintillionth |
| zepto | z | 10⁻²¹ | sextillionth |
| yocto | y | 10⁻²⁴ | septillionth |
| ronto | r | 10⁻²⁷ | octillionth |
| quecto | q | 10⁻³⁰ | nonillionth |
Quecto/quetta were ratified by the CGPM in 2022, extending the SI prefix range to handle yottabyte-scale data and sub-yoctosecond physics.
Paste one number per line. Output is in engineering notation by default; switch target format below.
Scientific notation writes a number as m × 10ⁿ with 1 ≤ |m| < 10. Engineering notation is the same but constrains n to a multiple of 3, so the mantissa lines up with SI prefixes (k, M, G, μ, n, …). E-notation is the compact ASCII form used by most programming languages: 1.23e6.
Floating-point arithmetic in JavaScript loses precision past ~17 significant digits and produces artifacts like 0.1 + 0.2 = 0.30000000000000004. This tool parses numbers as exact decimal strings and rounds only at display time, so very large and very small magnitudes round-trip cleanly.