Metric Prefixes Calculator — SI Unit Prefix Converter
Convert between SI metric prefixes from yocto to yotta. Enter a value with one prefix and see the equivalent in all other prefixes instantly. See also our Scientific Notation Calculator and Data Transfer Rate Calculator.
How to Convert Between Metric Prefixes
- Enter the numeric value you want to convert.
- Select the current prefix (e.g., kilo, milli, micro).
- Click Calculate to see the value in all SI prefixes.
- Each prefix represents a power of 10 relative to the base unit.
Formula
To convert from prefix A to prefix B:
value_B = value_A × (factor_A / factor_B)
Example: 5 kilometers to meters
5 × (10³ / 10⁰) = 5 × 1000 = 5000 meters
Example: 500 milligrams to micrograms
500 × (10⁻³ / 10⁻⁶) = 500 × 1000 = 500,000 μgExample
Convert 1 kilometer to other prefixes:
1 km = 1,000 m (base unit)
1 km = 100,000 cm (centimeters)
1 km = 1,000,000 mm (millimeters)
1 km = 0.001 Mm (megameters)
1 km = 1 × 10⁹ μm (micrometers)
SI Metric Prefixes Reference Table
| Prefix | Symbol | Factor | Power |
|---|---|---|---|
| tera | T | 1,000,000,000,000 | 10¹² |
| giga | G | 1,000,000,000 | 10⁹ |
| mega | M | 1,000,000 | 10⁶ |
| kilo | k | 1,000 | 10³ |
| hecto | h | 100 | 10² |
| deka | da | 10 | 10¹ |
| base | — | 1 | 10⁰ |
| deci | d | 0.1 | 10⁻¹ |
| centi | c | 0.01 | 10⁻² |
| milli | m | 0.001 | 10⁻³ |
| micro | μ | 0.000001 | 10⁻⁶ |
| nano | n | 0.000000001 | 10⁻⁹ |
| pico | p | 0.000000000001 | 10⁻¹² |
Frequently Asked Questions
What are SI prefixes?
SI prefixes are standardized multipliers used with metric units. They represent powers of 10, making it easy to express very large or very small quantities (e.g., kilometers, milligrams, nanoseconds).
How many SI prefixes are there?
There are 20 official SI prefixes, ranging from yocto (10⁻²⁴) to yotta (10²⁴). The most commonly used are milli, centi, kilo, mega, and giga.
What is the difference between mega and giga?
Mega (M) = 10⁶ = 1 million. Giga (G) = 10⁹ = 1 billion. Giga is 1000 times larger than mega.
Are binary prefixes (kibi, mebi) the same as SI prefixes?
No. Binary prefixes (Ki, Mi, Gi) use powers of 1024, while SI prefixes use powers of 1000. 1 kibibyte = 1024 bytes, but 1 kilobyte = 1000 bytes (SI definition).
Which prefix means one thousandth?
Milli (m) means one thousandth (10⁻³). For example, 1 millimeter = 0.001 meters, and 1 millisecond = 0.001 seconds.