Metric Prefix Converter

Convert a value between any two SI prefixes, such as nano to micro, milli to kilo or giga to mega, for any unit you like. The math is done on the digits, so results have no rounding errors.

Last updated: October 24, 2026

How to use the Metric Prefix Converter

1. Enter the value you want to convert.
2. Type the base unit (m, g, Hz, W…) so the result is labeled; it does not change the math.
3. Pick the From and To prefixes, e.g. kilo → milli.
4. Choose Squared or Cubed if your unit is an area or volume such as km² or cm³.
5. Read the result, the factor and the power-of-ten table for every prefix.

How metric prefix conversion works

A metric (SI) prefix is a power of ten placed in front of a unit: kilo means 10³, milli means 10⁻³, nano means 10⁻⁹. To convert, subtract the exponents and shift the decimal point:

result = value × 10(from exponent − to exponent) × power

Here power is 1 for ordinary units, 2 for squared units (area) and 3 for cubed units (volume). Example: 450 nm to µm is 450 × 10^{−9 − (−6)} = 450 × 10⁻³ = 0.45 µm.

SI prefix chart (quecto to quetta)

Tips to avoid prefix mistakes

• Case matters: M (mega, 10⁶) and m (milli, 10⁻³) differ by a factor of a billion. Likewise P (peta) vs p (pico), Z vs z and Y vs y.
• Use only one prefix per unit. Write nm, not mµm. The kilogram is the odd one out: its prefixes attach to the gram (mg, µg), never to "kg".
• Areas and volumes need the exponent multiplied: 1 cm² = 100 mm², 1 cm³ = 1,000 mm³ = 1 mL.
• Engineering notation uses only exponents that are multiples of 3 (k, M, G, m, µ, n). Centi, deci, deca and hecto are mainly used with meters, liters, grams and pascals.

Frequently asked questions

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