How To Convert Nanometers to Meters

nm to m Worked Unit Conversion Example Problem

Red laser
Nanometers are used to express wavelength of light. artpartner-images / Getty Images

This example problem demonstrates how to convert nanometers to meters or nm to m units. Nanometers are a unit most commonly used to measure wavelengths of light.

Nanometers to Meters Conversion Problem

The most common wavelength of the red light from a helium-neon laser is 632.1 nanometers. What is the wavelength in meters?


1 meter = 109 nanometers

Set up the conversion so the desired unit will be cancelled out.

In this case, we want m to be the remaining unit.

distance in m = (distance in nm) x (1 m/109 nm)
Note: 1/109 = 10-9
distance in m = (632.1 x 10-9) m
distance in m = 6.321 x 10-7 m


632.1 nanometers is equal to 6.321 x 10-7 meters.

Meters to Nanometers Example

It's a simple matter to convert meters to nanometers using the same unit conversion.

For example, the longest wavelength of red light (almost infrared) that most people can see is 7.5 x 10-7 meters. What is this in nanometers?

length in nm = (length in m) x (109 nm/m)

Note the meters unit cancels out, leaving nm.

length in nm = (7.5 x 10-7) x (109) nm

or, you could write this as:

length in nm = (7.5 x 10-7) x (1 x 109) nm

When you multiply powers of ten, all you need to do is add together the exponents. In this case, you add -7 to 9, which gives you 2:

length of red light in nm = 7.5 x 102 nm

This may be rewritten as 750 nm.