NIST SP 330
Decimal Multiples & Submultiples of SI Units
Table 3 from the NIST Guide for the Use of the International System of Units (SI) lists precise decimal scaling factors. Use it whenever you need to convert between kilo-, milli-, micro-, or larger prefixes without guessing.
Quick prefix converter
Enter a magnitude, pick any prefix on either side, and the converter will scale it using the exact powers of ten defined in Table 3.
Conversion sourcesTap or click to view references
The International System of Units (SI) — NIST Special Publication 330
National Institute of Standards and Technology (NIST). The SI Brochure (SP 330) is the definitive English edition of the BIPM SI tables. NIST’s edition lists the official constants and conversion factors tying inch-pound units to SI, which SwapUnits applies for length, mass, temperature, pressure, volume, and related conversions. See /standards/nist-si-tenfold for the complete decimal multiple/submultiple table. View source · View SI table
Decimal Multiples
| Prefix | Symbol | Factor |
|---|---|---|
| yotta | Y | 10^24 |
| zetta | Z | 10^21 |
| exa | E | 10^18 |
| peta | P | 10^15 |
| tera | T | 10^12 |
| giga | G | 10^9 |
| mega | M | 10^6 |
| kilo | k | 10^3 |
| hecto | h | 10^2 |
| deca | da | 10^1 |
Decimal Submultiples
| Prefix | Symbol | Factor |
|---|---|---|
| deci | d | 10^(-1) |
| centi | c | 10^(-2) |
| milli | m | 10^(-3) |
| micro | µ | 10^(-6) |
| nano | n | 10^(-9) |
| pico | p | 10^(-12) |
| femto | f | 10^(-15) |
| atto | a | 10^(-18) |
| zepto | z | 10^(-21) |
| yocto | y | 10^(-24) |
Source: NIST Special Publication 330. Return to nist.gov/pml/special-publication-330.