The nanometre is one billionth of a metre. It is formed by applying the SI prefix nano, meaning 10-9, to the metre, and is written nm. The prefix derives from the Greek nanos, meaning dwarf.
This is the working scale of modern optics and electronics. Visible light spans roughly 380 nm at the violet end to 750 nm at the red end, which makes the nanometre the standard unit for describing colour in physical terms. A laser pointer emitting at 532 nm is green; one at 650 nm is red. Ultraviolet light falls below 380 nm and infrared above 750 nm.
Biology uses the unit constantly. The DNA double helix is about 2 nm across. A typical virus measures between 20 and 300 nm. Cell membranes are around 7 nm thick. These dimensions sit below the resolution of conventional light microscopes, which is limited by the wavelength of the light itself to roughly 200 nm.
Semiconductor manufacturing made the nanometre familiar outside science. Process nodes have been labelled 90 nm, 45 nm, 14 nm, 5 nm and smaller. The figure no longer corresponds to any single measurable feature on the chip, having become a marketing designation rather than a physical dimension, but the underlying structures genuinely are nanometres across. A modern transistor gate is a few tens of atoms wide.
Nanotechnology takes its name from the unit and conventionally covers structures between 1 and 100 nm. Materials often behave differently in this range because surface effects begin to dominate bulk properties.
Measuring at this scale requires instruments that do not rely on visible light. Electron microscopes resolve features below one nanometre by using electrons, whose effective wavelength is far shorter than that of light. Atomic force microscopes work differently again, dragging a sharp tip across a surface and recording its deflection. Both were essential to the development of nanotechnology, since a field cannot advance far while its subject matter remains invisible.
One nanometre equals 10 ångströms, 1000 picometres, or 0.001 micrometres. A sheet of paper is roughly 100,000 nm thick.
| Unit | Symbol | 1 Nanometer equals | 1 of these equals | Converter |
|---|---|---|---|---|
| Ångström | Å | 10 Å | 0.1 nm | Nanometers to Ångströms |
| Micrometer | μm | 0.001 μm | 1000 nm | Nanometers to Micrometers |
| Millimeter | mm | 0.000001 mm | 1000000 nm | Nanometers to Millimeters |
| Centimeter | cm | 0.0000001 cm | 10000000 nm | Nanometers to Centimeters |
| Decimeter | dm | 0.00000001 dm | 100000000 nm | Nanometers to Decimeters |
| Meter | m | 0.000000001 m | 1000000000 nm | Nanometers to Meters |
| Decameter | dam | 1 × 10-10 dam | 10000000000 nm | Nanometers to Decameters |
| Hectometer | hm | 1 × 10-11 hm | 100000000000 nm | Nanometers to Hectometers |
| Kilometer | km | 1 × 10-12 km | 1000000000000 nm | Nanometers to Kilometers |
| Inch | in | 0.0000000393700787402 in | 25400000 nm | Nanometers to Inches |
| Hand | hh | 0.00000000984251968504 hh | 101600000 nm | Nanometers to Hands |
| Foot | ft | 0.00000000328083989501 ft | 304800000 nm | Nanometers to Feet |
| Yard | yd | 0.00000000109361329834 yd | 914400000 nm | Nanometers to Yards |
| Chain | ch | 4.9709695379 × 10-11 ch | 20116800000 nm | Nanometers to Chains |
| Furlong | fur | 4.9709695379 × 10-12 fur | 201168000000 nm | Nanometers to Furlongs |
| Mile | mi | 6.21371192237 × 10-13 mi | 1609344000000 nm | Nanometers to Miles |
| Nautical mile | nmi | 5.39956803456 × 10-13 nmi | 1852000000000 nm | Nanometers to Nautical miles |
| League | lea | 2.07123730746 × 10-13 lea | 4828032000000 nm | Nanometers to Leagues |
| Nautical league | nlea | 1.79985601152 × 10-13 nlea | 5556000000000 nm | Nanometers to Nautical leagues |
| Astronomical unit | au | 6.68458712227 × 10-21 au | 1.495978707 × 1020 nm | Nanometers to Astronomical units |
| Light year | ly | 1.05700083402 × 10-25 ly | 9.46073047258 × 1024 nm | Nanometers to Light years |
| Parsec | pc | 3.24077928944 × 10-26 pc | 3.08567758149 × 1025 nm | Nanometers to Parsecs |