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How much lighter is an electron than a proton?

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Bohr model diagram of a hydrogen atom showing a green nucleus labeled H, a single electron orbit, and text with atomic mass 1.008 and electron configuration 1. — atom The Bohr model describes the structure of atoms, in this case hydrogen.

An electron is significantly lighter than a proton. Specifically, the mass of an electron is approximately $1 / 1, 836$ the mass of a proton. Because of this vast difference, electrons are considered nearly massless when compared to protons or neutrons, and their mass is typically excluded when calculating the mass number of an atom.123