Electronvolts to megaelectronvolts (eV to MeV) converter

What is an electronvolts to megaelectronvolts converter?

An electronvolts to megaelectronvolts converter is an online tool that translates an amount of energy expressed in electronvolts (eV) into its equivalent in megaelectronvolts (MeV), and back again. Both units belong to the same family: the electronvolt is the energy gained by a single electron when it accelerates through a potential difference of one volt, and the megaelectronvolt is simply a larger multiple of it. Because these units span an enormous range of magnitudes in atomic, nuclear and particle physics, switching between them quickly is a routine part of reading data sheets, textbooks and experimental results.

How it works

The electronvolt and the megaelectronvolt are tied together by the standard metric prefix “mega,” which means one million. One megaelectronvolt therefore equals exactly 1,000,000 electronvolts. To go from electronvolts to megaelectronvolts you divide by one million; to go the other way you multiply by one million. The converter applies these factors instantly in both directions, so editing either field updates the other automatically. This makes it easy to compare, for example, the binding energy of an atomic electron (a few eV) with the energy released in a nuclear reaction (several MeV).

Formula for conversion

The relationship between electronvolts and megaelectronvolts is exact and prefix-based:

$\text{MeV} = \text{eV} \div 1{,}000{,}000$

$\text{eV} = \text{MeV} \times 1{,}000{,}000$

Electronvolts to megaelectronvolts conversion table

The table below lists common electronvolt values together with their megaelectronvolt equivalents, and a few megaelectronvolt values converted back to electronvolts.

Examples of conversion

Example 1: Converting electronvolts to megaelectronvolts

Convert 1,000,000 eV to megaelectronvolts. Divide by one million:

$1{,}000{,}000 \text{ eV} \div 1{,}000{,}000 = 1 \text{ MeV}$

Example 2: Converting megaelectronvolts to electronvolts

Convert 1 MeV to electronvolts. Multiply by one million:

$1 \text{ MeV} \times 1{,}000{,}000 = 1{,}000{,}000 \text{ eV}$

Example 3: A 5 MeV particle

A particle carrying 5 MeV of kinetic energy holds the following number of electronvolts:

$5 \text{ MeV} \times 1{,}000{,}000 = 5{,}000{,}000 \text{ eV}$

Example 4: Two million electronvolts

Convert 2,000,000 eV to megaelectronvolts:

$2{,}000{,}000 \text{ eV} \div 1{,}000{,}000 = 2 \text{ MeV}$

Notes

• The conversion is exact: 1 MeV is defined as precisely 1,000,000 eV, with no rounding involved.
• Electronvolts are convenient for atomic-scale energies such as ionization energies and photon energies of visible light.
• Megaelectronvolts are the natural scale for nuclear and particle physics, where reaction energies are typically a few MeV or more.
• Keeping consistent units throughout a calculation helps avoid factor-of-a-million errors, which are common when working across these scales.

Frequently asked questions

How many electronvolts are in one megaelectronvolt?

There are exactly 1,000,000 electronvolts in one megaelectronvolt, because the prefix “mega” stands for one million.

How do I convert electronvolts to megaelectronvolts?

Divide the number of electronvolts by 1,000,000. For example, 1,000,000 eV divided by one million equals 1 MeV.

How do I convert megaelectronvolts back to electronvolts?

Multiply the number of megaelectronvolts by 1,000,000. For instance, 5 MeV multiplied by one million equals 5,000,000 eV.

Why are electronvolts and megaelectronvolts used instead of joules?

Energies at the atomic and nuclear scale are extremely small when expressed in joules, leading to awkward exponents. Electronvolts and megaelectronvolts give tidy, human-readable numbers. If you do need joules, you can use our megaelectronvolt to joule converter.

Is the conversion between eV and MeV exact?

Yes. Unlike many unit conversions that rely on measured constants, the eV-to-MeV relationship is a fixed metric-prefix definition, so it is exact and never needs rounding.

Where are megaelectronvolts commonly seen?

Megaelectronvolts appear throughout nuclear physics and medical imaging, such as the energies of gamma rays, the rest energy of subatomic particles, and the beam energies used in radiotherapy.