What is the mass of a neutron?
The neutron mass is m_n = 1.67492749804e-27 kg (uncertainty ±9.5e-37). In energy units it is 939.56542052 MeV/c^2.
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| Value | 1.67492749804e-27 kg |
|---|---|
| Symbol | m_n |
| Energy equivalent | 939.56542052 MeV/c^2 |
| Uncertainty | ±9.5e-37 kg |
| Source | CODATA 2018 |
Frequently asked questions
What is the mass of a neutron in kg?
m_n = 1.67492749804e-27 kg, slightly larger than the proton mass.
What is the neutron mass in MeV?
The neutron rest mass is 939.56542052 MeV/c^2.
Why is the neutron heavier than the proton?
The neutron is about 1.293 MeV/c^2 heavier, which allows free neutrons to decay into a proton, electron, and antineutrino.
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