Metric Prefix Converter
Convert across all 24 SI prefixes, quecto to quetta, by powers of ten.
What it does
The metric system scales by tens, and prefixes name each jump. Kilo means a thousand, milli a thousandth, and every step between has its own name and symbol. Twenty four prefixes now span from quecto at 10^-30 to quetta at 10^30.
The tool above converts any prefix to any other. Enter the value, pick source and target, and read the converted number plus the scale jump. Defaults of 2.5 giga to mega open solved at 2500, times 1000.
The 2022 newcomers deserve attention because data outgrew the old top. Ronna and quetta extend upward for global data tallies, while ronto and quecto extend downward for quantum scale work. Everyday users meet kilo through nano; the outer prefixes serve research and infrastructure.
Case sensitivity is the classic trap. Capital M means mega at a million while lowercase m means milli at a thousandth, a billion fold apart. Likewise G is giga, k is kilo, and da for deca is the only two letter symbol.
Use the table to fix the everyday six in memory, then convert freely. Keep one rule: convert within the same base unit, meters to meters or watts to watts, never meters to grams.
How to use
- Enter the value in the source prefix.
- Pick the source prefix on the left.
- Pick the target prefix on the right.
- Read the converted number.
- Check the times line for the scale jump.
- Keep the base unit identical both sides.
Formula
- From exponent
- Power of ten of the source prefix.
- To exponent
- Power of ten of the target prefix.
- Gap
- Their difference; the result scales by 10 to this power.
All 24 SI prefixes from quecto (10^-30) to quetta (10^30), per the BIPM SI brochure and NIST. Prefixes attach to any SI unit; the page converts within one base unit, so pick matching quantities on both sides.
Worked example
Example: 2.5 G to M
Convert 2.5 giga to mega (same base unit).
- Giga means 10^9 and mega means 10^6.
- Gap: 9 - 6 = 3 powers of ten.
- Multiply: 2.5 x 10^3 = 2500.
- Result: 2.5 G equals 2500 M of the same unit.
- Works for watts, bytes with decimal SI, hertz, and meters alike.
- Reverse: 2500 M back to 2.5 G.
Reference table
| Prefix | Power | One of them equals |
|---|---|---|
| kilo (k) | 10^3 | 1000 base units |
| mega (M) | 10^6 | 1000 kilo |
| giga (G) | 10^9 | 1000 mega |
| milli (m) | 10^-3 | 0.001 base units |
| micro (µ) | 10^-6 | 0.001 milli |
| nano (n) | 10^-9 | 0.001 micro |
Limits
- Same base unit both sides; no unit changes.
- Decimal SI only; binary kibi differs.
- Symbols print in ASCII here (mu for µ).
- Extreme jumps exceed everyday precision.
Common mistakes
- Reading M as milli.
- Using SI math on binary memory sizes.
- Mixing base units mid conversion.
- Missing the 2022 four: ronna, quetta, ronto, quecto.
- Rounding away the small end of big jumps.
Try it yourself
Quick checks. Answers sit tucked under each question.
500 milli to base?
Milli is 10^-3 and base is 10^0, gap -3. 500 x 10^-3 = 0.5, times 0.001.
1 base unit to micro?
Gap 0 - (-6) = 6. 1 x 10^6 = 1000000, times 1000000.
4 TB to GB (decimal)?
Tera is 10^12, giga 10^9, gap 3. 4 x 1000 = 4000 GB in decimal SI.
Questions
When did ronna and quetta arrive?
2022, by the CGPM: ronna (10^27), quetta (10^30), ronto (10^-27), quecto (10^-30). Data volumes forced the extension.
Mega M or milli m?
Uppercase M for mega (10^6), lowercase m for milli (10^-3). Case carries a billion fold of meaning.
What is mu in the list?
Micro is the Greek mu, shown here as mu. In print it is µ, as in µg or µm.
Do bytes convert the same?
No. Computer memory uses binary kibi, mebi, gibi (1024 based). Telecom and disk makers often use decimal SI, which is why a 1 TB drive shows less.
Which prefixes matter daily?
Three: kilo, mega, giga upward and milli, micro, nano downward cover daily life. The rest serve science.
Why do centi and deci survive?
Centimeter with lengths, hectare with land, decibel with sound. Old habits plus convenient sizes keep them alive.