SI Prefixes Converter
Convert between SI prefixes: kilo, mega, giga, milli, micro, nano and every other power of ten from quecto (10⁻³⁰) to quetta (10³⁰).
Convert si prefixes
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Popular si prefixes conversions
SI Prefixes units
Every unit below converts to every other one in the calculator. Values are relative to the base unit, the base unit (no prefix) (×1).
| Unit | Symbol | System | Value |
|---|---|---|---|
| Quetta | Q | SI | = 1e+30 ×1 |
| Ronna | R | SI | = 1e+27 ×1 |
| Yotta | Y | SI | = 1e+24 ×1 |
| Zetta | Z | SI | = 1e+21 ×1 |
| Exa | E | SI | = 1e+18 ×1 |
| Peta | P | SI | = 1e+15 ×1 |
| Tera | T | SI | = 1000000000000 ×1 |
| Giga | G | SI | = 1000000000 ×1 |
| Mega | M | SI | = 1000000 ×1 |
| Kilo | k | SI | = 1000 ×1 |
| Hecto | h | SI | = 100 ×1 |
| Deca | da | SI | = 10 ×1 |
| Deci | d | SI | = 0.1 ×1 |
| Centi | c | SI | = 0.01 ×1 |
| Milli | m | SI | = 0.001 ×1 |
| Micro | µ | SI | = 0.000001 ×1 |
| Nano | n | SI | = 1e-9 ×1 |
| Pico | p | SI | = 1e-12 ×1 |
| Femto | f | SI | = 1e-15 ×1 |
| Atto | a | SI | = 1e-18 ×1 |
| Zepto | z | SI | = 1e-21 ×1 |
| Yocto | y | SI | = 1e-24 ×1 |
| Ronto | r | SI | = 1e-27 ×1 |
| Quecto | q | SI | = 1e-30 ×1 |
| Base unit (no prefix) | ×1 | SI | Base unit |
Base unit (no prefix) quick reference
| Base unit (no prefix) | Tera | Giga | Mega |
|---|---|---|---|
| 1 ×1 | = 1e-12 T | = 1e-9 G | = 0.000001 M |
| 10 ×1 | = 1e-11 T | = 1e-8 G | = 0.00001 M |
| 100 ×1 | = 1e-10 T | = 1e-7 G | = 0.0001 M |
| 1000 ×1 | = 1e-9 T | = 0.000001 G | = 0.001 M |
Among the 25 si prefixes units on this page, the smallest is the quecto (q) and the largest is the quetta (Q).
More si prefixes conversions
- Micro to Nanoµ → n
- Milli to Microm → µ
- Kilo to Base unit (no prefix)k → ×1
- Micro to Milliµ → m
- Milli to Base unit (no prefix)m → ×1
- Nano to Micron → µ
- Nano to Picon → p
- Tera to GigaT → G
- Giga to Base unit (no prefix)G → ×1
- Giga to TeraG → T
- Mega to Base unit (no prefix)M → ×1
- Micro to Base unit (no prefix)µ → ×1
- Base unit (no prefix) to Kilo×1 → k
- Base unit (no prefix) to Milli×1 → m
- Pico to Nanop → n
- Base unit (no prefix) to Giga×1 → G
- Base unit (no prefix) to Mega×1 → M
- Base unit (no prefix) to Micro×1 → µ
About si prefixes units
An SI prefix is a name for a power of ten that is attached to a unit: kilo means 10³, so a kilometer is 1000 meters. The 24 prefixes run from quecto (10⁻³⁰) to quetta (10³⁰). Ronna, quetta, ronto and quecto were added in 2022 to cope with very large and very small quantities, such as the mass of planets or the mass of an electron.
Here the prefix is converted on its own. Enter how many kilo units you have and the converter tells you how many mega units, milli units or base units that is. For example 5 kilo units are 0.005 mega units, 5000 base units and 5 000 000 milli units. Every factor is an exact power of ten, so results are exact.
Frequently asked questions
- What is the difference between kilo and kibi?
- Kilo (k) is the SI prefix for exactly 1000. Kibi (Ki) is the binary prefix for exactly 1024, written as KiB, MiB and GiB for memory sizes. Storage makers use the SI meaning (1 GB = 1 000 000 000 bytes), which is why a drive can look smaller in software that counts in gibibytes.
- Is it µ or u for micro?
- The correct symbol is the Greek letter µ. Many keyboards and plain-text systems use the letter u instead (for example uF for microfarad). Both are accepted in the search and calculator here.
- Why are some prefixes capital letters?
- Symbols for prefixes of 10⁶ and larger are capitals (M, G, T, P, E, Z, Y, R, Q) and smaller ones are lower case. The difference matters: m means milli (10⁻³) while M means mega (10⁶), a factor of one billion apart.
- How many tera units are in one base unit?
- One base unit = 1e-12 T (tera units).
- How many giga units are in one base unit?
- One base unit = 1e-9 G (giga units).
- How many mega units are in one base unit?
- One base unit = 0.000001 M (mega units).