Electronvolts to Joules Converter | Free eV to J Calculator

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Electronvolts to Joules Converter

Instantly Convert eV to J — Both Directions

Convert electronvolts to joules (eV → J) or joules to electronvolts (J → eV) instantly. Supports eV, keV, MeV, GeV, and TeV prefixes with exact formula, reference table, and real physics examples — free, no sign-up needed.

✅ eV → Joules

✅ Joules → eV

✅ keV / MeV / GeV / TeV

✅ Exact Formula

Electronvolts to Joules (eV to J) Converter

The electronvolt and the joule are both units of energy — one used in atomic and particle physics, the other the SI standard for everyday and engineering energy. This converter handles both directions instantly using the exact 2019 SI-defined conversion factor.

⚛️ What is an Electronvolt (eV)?

An electronvolt (eV) is the amount of kinetic energy gained by a single electron when it is accelerated through an electric potential difference of one volt in vacuum. Since 2019, one electronvolt is defined as exactly 1.602176634 × 10⁻¹⁹ joules — a fixed, exact value under the revised SI system. The eV is the standard energy unit in atomic, nuclear, and particle physics.

🔋 What is a Joule (J)?

The joule (J) is the SI derived unit of energy, equal to the work done by a force of one newton over a distance of one metre. It is used in everyday physics, engineering, and thermodynamics. One joule is an enormous amount of energy compared to the electronvolt — 1 J = 6.241509 × 10¹⁸ eV (over 6 quintillion electronvolts), which is why eV is preferred for sub-atomic scale calculations.

🔢 The Exact Conversion Factor

Since the 2019 redefinition of SI units, the conversion is exact: 1 eV = 1.602176634 × 10⁻¹⁹ J. This is derived from the elementary charge (e = 1.602176634 × 10⁻¹⁹ coulombs) multiplied by 1 volt. For the reverse, 1 J = 6.24150907 × 10¹⁸ eV. All conversions on this page use these exact values.

⚛️ Electronvolts ↔ Joules Converter

Choose direction, select prefix (eV/keV/MeV/GeV/TeV), enter value, and convert instantly

Value in Electronvolts (eV)

Result in Joules (J)

🔬 Or Select a Physics Energy Preset (auto-fills values)

Converted Value

— J

—

In keV

—

In MeV

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In GeV

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In attojoules (aJ)

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⚛️ How Electronvolts Convert to Joules — Visual Diagram

⚛️ Energy in eV

e.g. 1 eV

🔢 Conversion Factor

1.602176634 × 10⁻¹⁹

🔋 Energy in Joules

1.602 × 10⁻¹⁹ J

Joules = eV × 1.602176634 × 10⁻¹⁹ | Reverse: eV = Joules × 6.24150907 × 10¹⁸ | Conversion factor exact since 2019 SI redefinition

Electronvolts to Joules Formula

The conversion between electronvolts and joules uses the elementary charge as the exact conversion factor. Since the 2019 redefinition of SI units, the value of the elementary charge is fixed at exactly 1.602176634 × 10⁻¹⁹ coulombs — making the eV-to-joule conversion perfectly exact with no rounding.

⚛️ Electronvolts → Joules Formula

J = eV × 1.602176634 × 10⁻¹⁹

Example: 1 eV × 1.602176634×10⁻¹⁹ = 1.602×10⁻¹⁹ J

Example: 1 MeV = 1×10⁶ eV × 1.602×10⁻¹⁹ = 1.602×10⁻¹³ J

🔋 Joules → Electronvolts Formula

eV = J ÷ 1.602176634×10⁻¹⁹ (= J × 6.24150907×10¹⁸)

Example: 1 J ÷ 1.602×10⁻¹⁹ = 6.2415×10¹⁸ eV

Example: 1×10⁻¹³ J ÷ 1.602×10⁻¹⁹ = 624,150 eV ≈ 0.624 MeV

📊 eV Prefix Conversions to Joules

1 keV = 1,000 eV = 1.602176634 × 10⁻¹⁶ J

1 MeV = 1,000,000 eV = 1.602176634 × 10⁻¹³ J

1 GeV = 1×10⁹ eV = 1.602176634 × 10⁻¹⁰ J

1 TeV = 1×10¹² eV = 1.602176634 × 10⁻⁷ J

    💡 Quick Mental Estimate: One electronvolt is roughly
    1.6 × 10⁻¹⁹ joules. A useful shortcut: multiply eV by
    1.6 and shift the decimal 19 places to the left. For MeV,
    multiply by 1.6 and shift 13 places left. This gives a result accurate to
    about 0.1% of the exact value.
  

⚡ Quick Reference — Electronvolts to Joules

1 eV1.602 × 10⁻¹⁹ J

10 eV1.602 × 10⁻¹⁸ J

100 eV1.602 × 10⁻¹⁷ J

1 keV1.602 × 10⁻¹⁶ J

1 MeV1.602 × 10⁻¹³ J

1 GeV1.602 × 10⁻¹⁰ J

1 TeV1.602 × 10⁻⁷ J

1 J6.2415 × 10¹⁸ eV

Electronvolts to Joules Conversion Table

The table below lists electronvolt values from the sub-atomic scale up to particle accelerator energies, converted to joules using the exact factor 1 eV = 1.602176634 × 10⁻¹⁹ J. Scientific notation is used throughout as the numbers span over 30 orders of magnitude.

Electronvolts (eV)	Joules (J)	Prefix Scale	Physics Context
0.001 eV	1.602 × 10⁻²² J	meV range	Microwave photon energy
0.026 eV	4.165 × 10⁻²¹ J	meV range	Thermal energy at room temperature (kT)
1 eV	1.602 × 10⁻¹⁹ J	eV	Near-infrared photon / definition base
1.8 eV	2.884 × 10⁻¹⁹ J	eV	Red visible light photon
3.1 eV	4.967 × 10⁻¹⁹ J	eV	Violet visible light photon
13.6 eV	2.179 × 10⁻¹⁸ J	eV	Hydrogen atom ionisation energy
100 eV	1.602 × 10⁻¹⁷ J	eV	Soft X-ray photon
1 keV	1.602 × 10⁻¹⁶ J	keV	Hard X-ray / medical imaging
10 keV	1.602 × 10⁻¹⁵ J	keV	Dental X-ray photon energy
511 keV	8.187 × 10⁻¹⁴ J	keV	Electron rest-mass energy (mₑc²)
1 MeV	1.602 × 10⁻¹³ J	MeV	Gamma ray / nuclear energy scale
938.3 MeV	1.503 × 10⁻¹⁰ J	MeV	Proton rest-mass energy (mₚc²)
1 GeV	1.602 × 10⁻¹⁰ J	GeV	Particle accelerator scale
125 GeV	2.003 × 10⁻⁸ J	GeV	Higgs boson mass energy
1 TeV	1.602 × 10⁻⁷ J	TeV	LHC / high-energy particle physics
6.5 TeV	1.041 × 10⁻⁶ J	TeV	LHC proton beam energy (Run 2, 2026)

Joules to Electronvolts Conversion Table

Converting the other way — from joules to electronvolts — is equally straightforward. Divide the joule value by 1.602176634 × 10⁻¹⁹, or equivalently multiply by 6.24150907 × 10¹⁸. The table below covers joule values from the sub-atomic scale to everyday energy amounts.

Joules (J)	Electronvolts (eV)	eV Prefix	Context
1.602 × 10⁻¹⁹ J	1 eV	eV	Conversion base unit
1 × 10⁻¹⁸ J	6.242 eV	eV	Atomic energy scale
1 × 10⁻¹⁷ J	62.42 eV	eV	Soft X-ray scale
1 × 10⁻¹⁶ J	624.2 eV	eV	keV boundary
1 × 10⁻¹³ J	624,150 eV	≈ 0.624 MeV	Nuclear energy scale
1 × 10⁻¹⁰ J	6.242 × 10⁸ eV	≈ 0.624 GeV	Particle physics scale
1 × 10⁻³ J (1 mJ)	6.242 × 10¹⁵ eV	6,242 TeV	Millijoule — everyday scale
1 J	6.2415 × 10¹⁸ eV	6.2415 × 10⁶ TeV	SI base unit of energy
1 kJ	6.2415 × 10²¹ eV	6.2415 × 10⁹ TeV	Energy in a chocolate biscuit

Where Are Electronvolts to Joules Conversions Used?

The electronvolt is the dominant energy unit across multiple fields of modern physics and engineering. Understanding when and why to convert eV to joules is essential for students, researchers, and engineers working across different measurement systems.

⚛️ Particle Physics

Particle physics uses eV as its standard energy unit at every scale — from MeV (nuclear reactions) to GeV and TeV (collider experiments). The Large Hadron Collider (LHC) at CERN accelerates protons to 6.5 TeV = 1.04 × 10⁻⁶ joules per proton. Converting to joules reveals how incredibly small these energies are at the human scale — yet enough to probe the fundamental structure of matter.

💡 Photon & Light Energy

The energy of a photon is directly related to its frequency by E = hf (Planck's equation). Visible light photons carry energies of roughly 1.8–3.1 eV (red to violet). Physicists and optical engineers convert these eV values to joules when calculating laser power, photoelectric thresholds, and solar cell efficiency — since power in watts is joules per second.

☢️ Nuclear Physics

Nuclear binding energies, fission/fusion Q-values, and radioactive decay energies are all quoted in MeV. For instance, a uranium-235 fission reaction releases about 200 MeV = 3.2 × 10⁻¹¹ J per fission event. Converting MeV to joules is essential when calculating reactor thermal output, radiation dose (in grays), and neutron cross-sections in nuclear engineering.

💻 Semiconductor & Electronics

Semiconductor band gaps are measured in eV — silicon has a band gap of 1.12 eV, making it ideal for visible-light solar cells. Materials scientists convert eV band gaps to joules when modelling carrier energies, photon absorption thresholds, and LED emission wavelengths. The relationship E (J) = hc/λ connects eV, wavelength, and joules directly.

🌡️ Plasma & Fusion Physics

Plasma temperatures are often quoted in electronvolts rather than kelvin (using the relation 1 eV ≈ 11,604 K). Fusion reactor plasmas like those in ITER must reach temperatures of 10–20 keV (≈ 100–200 million °C). Converting plasma energies between eV and joules is routine in fusion research, magnetohydrodynamics, and astrophysical plasma modelling.

🎓 Education & Exam Physics

eV-to-joule conversion is a core skill in A-Level, IB, and university physics courses. Students regularly convert photon energies, ionisation energies, and work functions between eV and joules when solving photoelectric effect problems, atomic energy level calculations, and particle physics questions. The conversion factor 1 eV = 1.6 × 10⁻¹⁹ J appears in virtually every physics data booklet worldwide.

✅ eV vs Joule — Scale at a Glance: 1 joule = 6.24 × 10¹⁸ eV. This means that even a tiny amount of everyday energy (like lifting a 100g apple by 1 metre ≈ 1 J) contains an almost incomprehensible number of electronvolts — which is why physicists use eV at the atomic scale rather than joules.

Electronvolt and Joule — Key Facts

    📖 Historical Note: The electronvolt was introduced in the early
    20th century as particle accelerators were being developed, because joules were
    impractically large for describing sub-atomic energies. It became the universal
    energy currency of particle and atomic physics. The precise value was long measured
    experimentally, but since the 2019 SI redefinition, it is now
    exactly defined through the fixed elementary charge
    e = 1.602176634 × 10⁻¹⁹ C.
  

1 eV = 1.602176634 × 10⁻¹⁹ J (exact, since 2019 SI redefinition)
1 J = 6.24150907 × 10¹⁸ eV
1 keV = 10³ eV = 1.602 × 10⁻¹⁶ J — used for X-ray and medical physics
1 MeV = 10⁶ eV = 1.602 × 10⁻¹³ J — used for nuclear physics
1 GeV = 10⁹ eV = 1.602 × 10⁻¹⁰ J — used for particle accelerators
1 TeV = 10¹² eV = 1.602 × 10⁻⁷ J — used for LHC and cosmic ray physics
The electron rest-mass energy is 0.511 MeV = 8.187 × 10⁻¹⁴ J (mₑc²)
The proton rest-mass energy is 938.3 MeV = 1.503 × 10⁻¹⁰ J (mₚc²)
1 eV ≈ 11,604 kelvin — used for plasma temperature conversions
The Higgs boson mass energy is approximately 125 GeV = 2.0 × 10⁻⁸ J

⚠️ eV is NOT an SI Unit: The electronvolt is a non-SI unit accepted for use with the SI system, but it is not officially part of the SI. For formal scientific publications and engineering calculations, energies should ultimately be expressed in joules (J) or SI-derived units. The eV is used as a convenience unit in physics where joules would require unwieldy powers of 10.

🔗 Related Conversion: If you need to convert other energy units such as BTU or calories to joules (the SI energy unit that eV converts into), see our BTU to Joules Converter for a complete cross-reference of energy units used in thermodynamics and engineering.

Frequently Asked Questions — Electronvolts to Joules

How many joules is 1 electronvolt?

1 electronvolt (1 eV) is exactly 1.602176634 × 10⁻¹⁹ joules. This value has been exact since the 2019 redefinition of SI units, which fixed the elementary charge at exactly 1.602176634 × 10⁻¹⁹ coulombs. Since 1 eV is defined as the energy gained by one electron moving through 1 volt, and energy = charge × voltage, 1 eV = (1.602176634 × 10⁻¹⁹ C) × (1 V) = 1.602176634 × 10⁻¹⁹ J.

How do I convert electronvolts to joules?

To convert electronvolts to joules, multiply the number of electronvolts by 1.602176634 × 10⁻¹⁹. The formula is: J = eV × 1.602176634 × 10⁻¹⁹. For example: 5 eV × 1.602×10⁻¹⁹ = 8.011×10⁻¹⁹ J. For larger units: 1 MeV = 1×10⁶ eV × 1.602×10⁻¹⁹ = 1.602×10⁻¹³ J. Use the converter at the top of this page for instant results without manual calculation.

How do I convert joules to electronvolts?

To convert joules to electronvolts, divide the joule value by 1.602176634 × 10⁻¹⁹ (or equivalently, multiply by 6.24150907 × 10¹⁸). The formula is: eV = J ÷ 1.602176634 × 10⁻¹⁹. For example: 3.204 × 10⁻¹⁹ J ÷ 1.602×10⁻¹⁹ = 2 eV. For 1 J: 1 ÷ 1.602×10⁻¹⁹ = 6.2415×10¹⁸ eV — over 6 quintillion electronvolts.

What is 1 MeV in joules?

1 MeV (megaelectronvolt) = 1,000,000 eV = 1 × 10⁶ × 1.602176634 × 10⁻¹⁹ J = 1.602176634 × 10⁻¹³ joules. MeV is the standard energy unit in nuclear physics. For reference: the electron rest-mass energy is 0.511 MeV (= 8.187 × 10⁻¹⁴ J) and the proton rest-mass energy is 938.3 MeV (= 1.503 × 10⁻¹⁰ J).

Why do physicists use electronvolts instead of joules?

Physicists use electronvolts because the energies involved in atomic and subatomic processes are unimaginably small in joules — for example, the ionisation energy of hydrogen is 13.6 eV, which is only 2.18 × 10⁻¹⁸ joules. Expressing this as 0.0000000000000000021... joules is impractical. Electronvolts scale naturally to the atomic world: photon energies are a few eV, nuclear energies are MeV, and particle accelerator energies are GeV–TeV — all compact, manageable numbers.

What is the difference between eV, keV, MeV, GeV, and TeV?

These are all electronvolt units with metric prefixes representing different energy scales: eV (electronvolt) — atomic/molecular scale (visible light, ionisation energies). keV (kiloelectronvolt, 10³ eV) — X-ray and low-energy nuclear scale. MeV (megaelectronvolt, 10⁶ eV) — nuclear physics, gamma rays, beta decay. GeV (gigaelectronvolt, 10⁹ eV) — particle physics, accelerator experiments. TeV (teraelectronvolt, 10¹² eV) — highest-energy particle physics, LHC, cosmic rays. Each step is 1,000× larger than the previous.

What everyday energy does 1 electronvolt represent?

1 electronvolt (1.602 × 10⁻¹⁹ J) is an extraordinarily tiny amount of energy by everyday standards. To put it in perspective: lifting a single grain of sand (≈ 1 mg) by 1 mm requires about 10 billion electronvolts (10 GeV). The energy in a AA battery (3 Wh ≈ 10,800 J) equals about 6.7 × 10²² eV. The eV is only "large" at the quantum and atomic scale — which is exactly why it's the preferred unit there.

Physics Energy Resources & Further Reading

⚛️ NIST Physical Constants

The exact value of the elementary charge (and therefore the electronvolt) is maintained by the National Institute of Standards and Technology (NIST). Since the 2019 SI redefinition, 1 eV = 1.602176634 × 10⁻¹⁹ J exactly.

NIST eV → J →

🔥 Energy Unit Conversions

The joule is the SI unit that connects electronvolts to everyday energy scales. For thermodynamic and heat energy conversions — such as BTU, calories, and kilowatt-hours — see our dedicated energy converters.

BTU to Joules →

🌬️ Pressure in Physics

Pressure and energy are related concepts in thermodynamics — both appear in the ideal gas law and equations of state. Convert between pressure units used in plasma physics and gas law calculations.

Atm to Pascals →