Metric Prefixes converter
Move a quantity between SI prefixes without counting zeros.
Converter
Quick pairs
tap to loadOne kilo (10³) in every metric prefixes unit
24 rows| Unit | Symbol | 1 k equals |
|---|---|---|
| Quetta (10³⁰) | Q | 1e-27 |
| Ronna (10²⁷) | R | 1e-24 |
| Yotta (10²⁴) | Y | 1e-21 |
| Zetta (10²¹) | Z | 1e-18 |
| Exa (10¹⁸) | E | 1e-15 |
| Peta (10¹⁵) | P | 1e-12 |
| Tera (10¹²) | T | 1e-9 |
| Giga (10⁹) | G | 1e-6 |
| Mega (10⁶) | M | 0.001 |
| Hecto (10²) | h | 10 |
| Deka (10¹) | da | 100 |
| None (×1) | 1 | 1,000 |
| Deci (10⁻¹) | d | 10,000 |
| Centi (10⁻²) | c | 100,000 |
| Milli (10⁻³) | m | 1,000,000 |
| Micro (10⁻⁶) | µ | 1,000,000,000 |
| Nano (10⁻⁹) | n | 1e12 |
| Pico (10⁻¹²) | p | 1e15 |
| Femto (10⁻¹⁵) | f | 1e18 |
| Atto (10⁻¹⁸) | a | 1e21 |
| Zepto (10⁻²¹) | z | 1e24 |
| Yocto (10⁻²⁴) | y | 1e27 |
| Ronto (10⁻²⁷) | r | 1e30 |
| Quecto (10⁻³⁰) | q | 1e33 |
How the kilo (10³) to mega (10⁶) conversion works
This converter's reference row is "None (×1)" — the un-prefixed base unit itself, whether that's a meter, a gram, a second or anything else measured in SI. Every prefix above it scales up by powers of ten: kilo is ×1,000, mega is ×1,000,000, giga is ×1,000,000,000, all the way to quetta at ×10³⁰. Every prefix below it scales down the same way: milli is ×0.001, micro is ×0.000001, down to quecto at ×10⁻³⁰.
The featured pair is kilo to mega. Divide kilo's factor (1,000) by mega's factor (1,000,000) to get: M = k × 0.001. Reversing it means multiplying by 1,000 instead; moving one prefix tier up or down the SI scale is always a clean power of ten.
2.5 kilograms expressed in megagrams (metric tonnes, essentially) becomes 2.5 × 0.001 = 0.0025 Mg. Going the other direction, 3 micrograms converts to 3 × 1,000 = 3,000 nanograms, since micro sits exactly three decimal places above nano.
Metric prefixes attach to any SI unit, which is why this single converter is useful across completely different fields: kilometers and milligrams in everyday life, gigahertz in electronics, nanometers in semiconductor manufacturing, picograms in medical lab results, and femtoseconds in ultrafast laser physics. Rather than memorizing a separate scale for each discipline, the same ×1,000 step between adjacent prefixes applies everywhere.
The highest-stakes mix-up in this category is confusing milli (×0.001) with micro (×0.000001), a thousand-fold difference that, in medicine, is a classic root cause of serious dosing errors when "mg" and "µg" (or the written abbreviation "mcg") are misread or mistyped. Because the two prefixes look and sound similar, many hospitals require micrograms to be written out in full rather than abbreviated, specifically to avoid this error.
The newest prefixes on this list — ronna, quetta, ronto and quecto — were only added to the SI in 2022 to keep pace with data volumes (a quettabyte-scale measure of the world's cumulative digital data) and with microscopic measurements in physics, extending the prefix system beyond yotta and yocto, which had been the largest and smallest official prefixes for decades before that.
Questions
How many mega units are in one kilo unit?
One kilo equals 0.001 mega; in other words, it takes 1,000 kilo-units to make one mega-unit.
Which metric prefixes does this converter cover?
25 prefixes spanning the full current SI range, from quetta (10³⁰) down to quecto (10⁻³⁰), plus the unprefixed base unit itself, listed as "None (×1)."
Are metric prefix conversions ever approximate?
No, unlike most other categories on this site, every conversion here is an exact power of ten with no rounding at all. The only practical limit is how many digits a calculator or display can show for the largest and smallest prefixes.
When would I use centi instead of milli?
Centi (×0.01) is mostly limited to the centimeter in everyday use; most other quantities skip straight from the base unit to milli. If you're not working with length, milli, micro or nano are far more likely to be the prefix you actually want.
Are hecto and deka ever used in practice?
Rarely, but not never: hectoliters (hL) are the standard unit for reporting wine, beer and fuel production volumes in much of Europe, and dekagrams (dag) still appear on grocery scales in a few Central European countries. Outside those niches, most fields skip directly from the base unit to kilo or down to milli.
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