Inches to Nanometers (in to nm)

1 inch equals 25,400,000 nanometers exactly.

1 inch = 25,400,000 nanometers

How to convert inches to nanometers

To convert inches to nanometers, multiply the number of inches by 25,400,000. This factor is exact. To go the other way, multiply nanometers by 3.937007874×10⁻⁸ (rounded).

nanometers = inches × 25,400,000

Example: 10 inches = 254,000,000 nanometers.

About these units

Inch (in)

US & ImperialCurrent unit

1/12 of a foot. Defined as exactly 25.4 millimeters since 1959, when the US and Commonwealth countries agreed a common international inch.

Latin uncia, meaning one-twelfth, is the root of both inch and ounce, and it passed into Old English as ynce. Roman measurers divided their foot into twelve unciae, and the English inch kept that twelfth. After 1066 an inch was reckoned as three barleycorns, and a 1324 statute attributed to Edward II spelled out the definition as three grains of barley, dry and round, placed end to end lengthwise. For centuries the inch was simply a twelfth of a foot, or a thirty-sixth of a yard, and the US and UK each kept their own copy of the standard yard.

Those copies differed slightly until the 1959 international agreement fixed the yard at exactly 0.9144 meter, which made the inch exactly 25.4 millimeters. The US adopted it in 1959 and the UK ratified it in 1963, effective 1964. Today the inch is still the customary unit in the United States and Canada, and the UK keeps it on road signs. Worldwide it also names display diagonals, wheel rims, tire codes and pipe sizes.

1 inch = 0.0254 meters (exactly).

Sources: Wikipedia: Inch; Wikipedia: Yard; NIST Guide to the SI, Appendix B.8: conversion factors

Nanometer (nm)

Metric (SI)Current unit

One billionth of a meter. Used for the wavelength of light (visible light is about 400–700 nm) and for chip feature sizes.

Greek for dwarf gave nano- its name, and the nanometer was once called something clumsier: the millimicrometre, or more often the millimicron, written mμ, since it is a thousandth of a micrometer. The prefix nano- was among those officially adopted when SI prefixes were first introduced in 1960, and the nanometer grew into the standard unit for optics and microelectronics. It sits a factor of ten above the older ångström, which is 0.1 nm and is still used for atomic distances.

Visible light spans roughly 400 to 700 nm, which is why color and spectroscopy are quoted this way. A helium atom is about 0.06 nm across and a ribosome about 20 nm. Chip makers have used nanometers since the late 1980s in names for manufacturing generations such as 32 nm and 22 nm. Those are labels for successive generations in the industry roadmap, and they describe typical feature sizes rather than one exact measurement. Readers should also beware that nm is sometimes written informally for the nautical mile.

1 nanometer = 1×10⁻⁹ meters (exactly).

Sources: Wikipedia: Nanometre; Wikipedia: Metric prefix; Wikipedia: Nautical mile

Related conversions

See all length units.