What Is the Relative Mass of an Electron?

By Staff WriterLast Updated Apr 8, 2020 3:03:34 PM ET

Electrons have a relative mass of 9.1 x 10^-31 kilograms, or 0.51 megaelectron volts. They are a lot smaller than protons and neutrons; and, an electron is roughly 0.054 percent of the mass of one neutron.