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?**Solution:**

1 meter = 10^{9} 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/10^{9} nm)

Note: 1/10^{9} = 10^{-9}

distance in m = (632.1 x 10^{-9}) m

distance in m = 6.321 x 10^{-7} m**Answer:**

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 (10^{9} nm/m)

Note the meters unit cancels out, leaving nm.

length in nm = (7.5 x 10^{-7}) x (10^{9}) nm

or, you could write this as:

length in nm = (7.5 x 10^{-7}) x (1 x 10^{9}) 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 10^{2} nm

This may be rewritten as 750 nm.