Metric Prefix Converter
Result
1.0000e+3
How it works
SI metric prefixes scale any base unit by powers of 10. Knowing prefix names, symbols, and exponents is essential in science, engineering, computing, and medicine. The Metric Prefix Converter converts values between any two SI prefix levels and provides a complete reference table from yocto (10⁻²⁴) to yotta (10²⁴).
**Complete prefix table** yotta (Y) = 10²⁴; zetta (Z) = 10²¹; exa (E) = 10¹⁸; peta (P) = 10¹⁵; tera (T) = 10¹²; giga (G) = 10⁹; mega (M) = 10⁶; kilo (k) = 10³; hecto (h) = 10²; deca (da) = 10¹; [base] = 10⁰; deci (d) = 10⁻¹; centi (c) = 10⁻²; milli (m) = 10⁻³; micro (µ) = 10⁻⁶; nano (n) = 10⁻⁹; pico (p) = 10⁻¹²; femto (f) = 10⁻¹⁵; atto (a) = 10⁻¹⁸; zepto (z) = 10⁻²¹; yocto (y) = 10⁻²⁴.
**Conversion algorithm** To convert N gigahertz to megahertz: 1 GHz = 10⁹ Hz; 1 MHz = 10⁶ Hz. Factor = 10⁹/10⁶ = 10³ = 1000. So N GHz = N × 1000 MHz. General rule: multiply by 10^(source_exponent − target_exponent).
**Common practical conversions** 1 km = 1000 m = 100,000 cm = 1,000,000 mm. 1 mg = 0.001 g = 1,000 µg. 1 GHz = 1000 MHz = 10⁹ Hz. 1 kW = 1000 W = 1,000,000 mW. 1 µm = 1000 nm (micrometre to nanometre). Wavelength of visible light: 380–700 nm = 0.38–0.70 µm.
**New 2022 prefixes** IEC added four new SI prefixes in 2022: ronna (R) = 10²⁷, quetta (Q) = 10³⁰ (larger), ronto (r) = 10⁻²⁷, quecto (q) = 10⁻³⁰ (smaller). These are needed for cosmology and particle physics at the extreme ends.
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Frequently Asked Questions
- The SI prefix kilo is always lowercase 'k' (1 km = 1 kilometre). The symbol for kelvin (the SI unit of temperature) is uppercase 'K'. This distinction is important: 1 kJ means 1 kilojoule; 1 KJ would be incorrect notation (K is kelvin, not a prefix). Similarly: 1 MW = 1 megawatt (M is mega); 1 mW = 1 milliwatt (m is milli). Prefix symbols are case-sensitive — M (mega, 10⁶) vs. m (milli, 10⁻³) is a factor of 10⁹ difference if confused. Always check capitalisation when reading or writing SI units.
- SI kilo = 10³ = 1000 (decimal). Computer storage traditionally used kilo = 2¹⁰ = 1024 (binary) because addressing memory is done in powers of 2. The IEC introduced binary prefixes in 1998 to eliminate ambiguity: kibibyte (KiB) = 2¹⁰ = 1024 bytes; kilobyte (kB) = 10³ = 1000 bytes. The difference grows: at the terabyte level, 1 TiB = 1.0995 TB (≈10% larger). Most operating systems still display binary values with SI labels, causing the well-known 'why does my drive show less space than advertised' confusion.
- 1 nanometre (nm) = 10⁻⁹ metres = one billionth of a metre ≈ 10 hydrogen atoms in a row. Semiconductor manufacturing uses nanometres to describe transistor feature sizes — the 'N-nm process node'. Intel's 10nm process (introduced 2019) has transistors with features approximately 10–15nm in critical dimensions. Modern chips (TSMC's 3nm, 2nm nodes in 2023–2025) pack billions of transistors by shrinking features to atomic-scale dimensions. A silicon atom is ~0.24nm in diameter, so a 3nm feature is only about 12 silicon atoms wide.
- 1 micrometre (µm) = 10⁻⁶ m; 1 nanometre (nm) = 10⁻⁹ m. Factor: 1 µm = 1000 nm; 1 nm = 0.001 µm. Multiply by 1000 to go from µm to nm; divide by 1000 to go from nm to µm. Example: 0.5 µm = 500 nm (a bacterium is about 0.5–5 µm = 500–5000 nm). Visible light wavelength: 380–700 nm = 0.38–0.70 µm. Human hair width: ~70 µm = 70,000 nm. Red blood cell diameter: ~8 µm = 8000 nm.