⚙️ Metric Prefixes Reference Table
The International System of Units (SI) defines 24 prefixes that scale any base unit by powers of ten. From yotta at 10²⁴ to yocto at 10⁻²⁴, these prefixes are used in science, engineering, computing, and everyday measurement.
| Prefix | Symbol | Power |
|---|---|---|
| Yotta | Y | 10²⁴ |
| Zetta | Z | 10²¹ |
| Exa | E | 10¹⁸ |
| Peta | P | 10¹⁵ |
| Tera | T | 10¹² |
| Giga | G | 10⁹ |
| Mega | M | 10⁶ |
| Kilo | k | 10³ |
| Hecto | h | 10² |
| Deca | da | 10¹ |
| (base) | — | 10⁰ |
| 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 |
How to Use Metric Prefixes
Attach any prefix to a base unit to scale it. The most common base units are the meter (length), gram (mass), liter (volume), second (time), and byte (digital storage).
For example: kilometer = 1,000 meters; milligram = 0.001 grams; gigabyte = 1,000,000,000 bytes (SI) or 2³⁰ bytes (binary, sometimes called gibibyte).
Frequently Asked Questions
What is the metric prefix for 1,000?
Kilo (k) = 10³ = 1,000. Example: 1 kilometer (km) = 1,000 meters.
What is the metric prefix for one million?
Mega (M) = 10⁶ = 1,000,000. Example: 1 megabyte (MB) = 1,000,000 bytes.
What is the prefix for one-thousandth?
Milli (m) = 10⁻³ = 0.001. Example: 1 millimeter (mm) = 0.001 meters.
What is the prefix for one-billionth?
Nano (n) = 10⁻⁹. Example: 1 nanometer (nm) = 0.000000001 meters, used in semiconductor manufacturing.