How to Convert Angstroms to Nanometers

This example problem demonstrates how to convert angstroms to nanometers. Angstroms (Å) and nanometers (nm) are both linear measurements used to express extremely small distances.

Problem

The spectra of the element mercury have a bright green line with a wavelength of 5460.47 Å. What is the wavelength of this light in nanometers?

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Converting Nanometers to Angstroms

By Anne Marie Helmenstine, Ph.D.

Solution

1 Å = 10^-10 m
1 nm = 10^-9 m
Set up the conversion so the desired unit will be canceled out. In this case, we want nanometers to be the remaining unit.
wavelength in nm = (wavelength in Å) x (10^-10 m/1 Å) x (1 nm/10^-9 m)
wavelength in nm = (wavelength in Å) x (10^-10/10^-9 nm/Å)
wavelength in nm = (wavelength in Å) x (10^-1) nm/Å)
wavelength in nm = (5460.47/10) nm
wavelength in nm = 546.047 nm​

Answer

The green line in mercury's spectra has a wavelength of 546.047 nm.

It may be easier to remember there are 10 angstroms in 1 nanometer. This would mean that 1 angstrom is a tenth of a nanometer and a conversion from angstroms to nanometers would mean moving the decimal place one position to the left.

Remember to check your significant figures when reporting measurements. In science, even if you do the calculation correctly, your answer is technically incorrect if not reported using significant digits.