eV to MeV Converter
Free electronvolt to megaelectronvolt calculator with keV, GeV, joules, photon wavelength and frequency.
Convert eV to MeV and MeV to eV
Type any energy value and pick its unit. This ev to mev calculator handles electronvolt to megaelectronvolt and megaelectronvolt to electronvolt conversion, plus mev to ev conversion for any value, across the full ev mev kev gev scale.
Please enter a non-negative number.
How to convert eV to MeV
The ev to mev conversion is a simple division, because the mega prefix means exactly one million:
Example: convert 2,500,000 eV to MeV by dividing: 2,500,000 / 1,000,000 = 2.5 MeV. To convert 2.5 MeV to eV, multiply: 2.5 x 1,000,000 = 2,500,000 eV.
eV, keV, MeV, GeV scale
Each step up the electronvolt scale multiplies by 1,000. This ladder covers everything from visible light photons to particle accelerator energies:
| Unit | Name | Equals |
|---|---|---|
| eV | electronvolt | 1 eV (base unit) |
| keV | kiloelectronvolt | 1,000 eV |
| MeV | megaelectronvolt | 1,000 keV = 1,000,000 eV |
| GeV | gigaelectronvolt | 1,000 MeV = 1,000,000,000 eV |
So a kev to mev conversion divides by 1,000, a mev to kev conversion multiplies by 1,000, a gev to mev conversion divides by 1,000, and a kev to ev conversion multiplies by 1,000.
Quick answers: how many eV in 1 MeV? Exactly 1,000,000. So 1 MeV to eV is 1,000,000 eV, and 1 eV to MeV is 1e-06 MeV.
Common energies in eV, keV and MeV
Reference energies from atomic physics, medical imaging, and particle physics, shown across the ev to mev scale:
| Source | eV | keV | MeV | GeV | Field |
|---|---|---|---|---|---|
| Thermal neutron | 0.025 | 2.5e-05 | 2.5e-08 | 2.5e-11 | Nuclear reactors |
| Red light photon (~650 nm) | 1.907449207 | 0.001907449207 | 1.907449207e-06 | 1.907449207e-09 | Optics |
| Green laser photon (532 nm) | 2.330530046 | 0.002330530046 | 2.330530046e-06 | 2.330530046e-09 | Optics |
| Hydrogen ionization energy | 13.60569312 | 0.01360569312 | 1.360569312e-05 | 1.360569312e-08 | Atomic physics |
| PET scan annihilation photon | 511000 | 511 | 0.511 | 0.000511 | Medical imaging |
| Electron rest energy | 510998.95 | 510.99895 | 0.51099895 | 0.00051099895 | Particle physics |
| Cobalt-60 gamma ray | 1332492 | 1332.492 | 1.332492 | 0.001332492 | Radiotherapy |
| Proton rest energy | 938272081.3 | 938272.0813 | 938.2720813 | 0.9382720813 | Particle physics |
Wavelength and frequency rows treat the energy as a photon (E = hc / wavelength). Values computed from exact SI constants.
Frequently asked questions
How many eV are in 1 MeV?
Exactly 1,000,000 eV. The prefix mega (M) means one million, so 1 MeV equals 1,000,000 eV by definition. Likewise 2 MeV equals 2,000,000 eV, and 0.5 MeV equals 500,000 eV.
How do I convert eV to MeV?
Divide the eV value by 1,000,000. Formula: MeV = eV / 1,000,000. Example: 2,500,000 eV / 1,000,000 = 2.5 MeV.
How do I convert MeV to eV?
Multiply the MeV value by 1,000,000. Formula: eV = MeV x 1,000,000. Example: 2.5 MeV x 1,000,000 = 2,500,000 eV.
What is 500 eV in MeV?
500 eV equals 0.0005 MeV. Calculation: 500 / 1,000,000 = 0.0005.
Where does keV fit between eV and MeV?
keV sits exactly in the middle of the ladder: 1 keV = 1,000 eV, and 1 MeV = 1,000 keV. The full scale goes eV to keV to MeV to GeV, each step multiplying by 1,000.
How many MeV are in 1 GeV?
1 GeV equals 1,000 MeV, which is 1,000,000,000 eV. The prefix giga (G) means one billion. Particle accelerators work in the GeV and TeV range.
How many joules is 1 eV?
1 eV equals 1.602176634x10^-19 joules. This is an exact value fixed by the SI definition of the volt and the elementary charge.
How many joules is 1 MeV?
1 MeV equals 1.602176634x10^-13 joules, which is 1,000,000 times the energy of 1 eV.
What color of light is a 2 eV photon?
A 2 eV photon has a wavelength of about 620 nm, which is red light. Wavelength = 1239.842 eV·nm / 2 eV = 619.9209922 nm, commonly rounded to 620 nm.
What is the rest energy of an electron in MeV?
An electron at rest has an energy of 510.99895 keV, which equals 0.51099895 MeV, commonly rounded to 0.511 MeV. This is why 0.511 MeV annihilation photons appear in PET scans.
What are typical X-ray and gamma ray energies in keV and MeV?
Medical X-rays are typically tens of keV, for example 60 keV equals 0.06 MeV. Gamma rays from cobalt-60, used in radiotherapy, have energies of 1.17 MeV and 1.332492 MeV (1332.492 keV).
Why do physicists use electronvolts instead of joules?
Electronvolts keep the numbers readable. A proton at rest is 938.2720813 MeV, but only 1.503277605x10^-10 joules. In particle physics, radiology, and semiconductor work, MeV and keV are far more practical than tiny decimal joules.
Can electronvolts be used to measure mass?
Yes, through E = mc^2. Particle masses are quoted in eV/c^2: an electron is 0.51099895 MeV/c^2, usually rounded to 0.511 MeV/c^2, and a proton is about 938.272 MeV/c^2.
What is the energy of a thermal neutron in MeV?
A thermal neutron has an energy of 0.025 eV, which equals 2.5x10^-8 MeV. Thermal neutrons drive fission in nuclear reactors.
What is an electronvolt?
The electronvolt definition is simple: the energy one electron gains crossing an electric potential of one volt, exactly 1.602176634x10^-19 joules (also written electron volt). The eV unit suits atomic-scale energies such as visible light photons, while the MeV unit (megaelectronvolt) is the standard energy unit in particle physics, radiology, and semiconductor device physics, where the electron rest mass energy of 0.511 MeV is a daily reference. Typical searches this converter answers include 1 eV in joules, MeV to joules, and electron volt to MeV, alongside straight eV to MeV conversion.
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