Unit Converter

Energy Converter

Joule (J)

Watt-hour (Wh)

Kilowatt-hour (kWh)

Calorie (cal)

Erg (erg)

Kilojoule (kJ)

Megajoule (MJ)

Kilocalorie (kcal)

Kilojoule per Mole (kJ/mol)

Kilocalorie per Mole (kcal/mol)

Megajoule per Mole (MJ/mol)

Megacalorie per Mole (Mcal/mol)

Hartree (Ha)

Rydberg (Ry)

Electron Volt (eV)

Mega Electron Volt (MeV)

Giga Electron Volt (GeV)

Tera Electron Volt (TeV)

Peta Electron Volt (PeV)

e²/Bohr (e²/Bohr)

e²/Nanometer (e²/nm)

e²/Angstrom (e²/Å)

amu·Å²/fs² (amu·Å²/fs²)

amu·nm²/ps² (amu·nm²/ps²)

Temperature (Kelvin) (K)

Mass Energy (kg) (kg(c²))

Atomic Mass Unit Energy (amu(c²))

Energy Unit Conversion Chart

1 J = 0.000277778 Wh

Joule (J) to Watt-hour (Wh)

1 J = 2.77778e-7 kWh

Joule (J) to Kilowatt-hour (kWh)

1 J = 0.239006 cal

Joule (J) to Calorie (cal)

1 J = 0.00100000 kJ

Joule (J) to Kilojoule (kJ)

1 J = 0.00000100000 MJ

Joule (J) to Megajoule (MJ)

1 J = 0.000239006 kcal

Joule (J) to Kilocalorie (kcal)

1 J = 6,241,509,074,460,763,000 eV

Joule (J) to Electron Volt (eV)

1 J = 6,241,509,074,460.763 MeV

Joule (J) to Mega Electron Volt (MeV)

1 J = 229,371,227,839,632,480 Ha

Joule (J) to Hartree (Ha)

1 J = 10,000,000 erg

Joule (J) to Erg (erg)

Watt-hour (Wh) to Joule (J)

1 Wh = 0.00100000 kWh

Watt-hour (Wh) to Kilowatt-hour (kWh)

1 Wh = 860.421 cal

Watt-hour (Wh) to Calorie (cal)

Watt-hour (Wh) to Kilojoule (kJ)

1 Wh = 0.00360000 MJ

Watt-hour (Wh) to Megajoule (MJ)

1 Wh = 0.860421 kcal

Watt-hour (Wh) to Kilocalorie (kcal)

1 Wh = 22,469,432,668,058,747,000,000 eV

Watt-hour (Wh) to Electron Volt (eV)

1 Wh = 22,469,432,668,058,744 MeV

Watt-hour (Wh) to Mega Electron Volt (MeV)

1 Wh = 825,736,420,222,677,000,000 Ha

Watt-hour (Wh) to Hartree (Ha)

1 Wh = 36,000,000,000 erg

Watt-hour (Wh) to Erg (erg)

1 kWh = 3,600,000 J

Kilowatt-hour (kWh) to Joule (J)

1 kWh = 1,000 Wh

Kilowatt-hour (kWh) to Watt-hour (Wh)

1 kWh = 860,420.65 cal

Kilowatt-hour (kWh) to Calorie (cal)

1 kWh = 3,600 kJ

Kilowatt-hour (kWh) to Kilojoule (kJ)

Kilowatt-hour (kWh) to Megajoule (MJ)

1 kWh = 860.421 kcal

Kilowatt-hour (kWh) to Kilocalorie (kcal)

1 kWh = 22,469,432,668,058,746,000,000,000 eV

Kilowatt-hour (kWh) to Electron Volt (eV)

1 kWh = 22,469,432,668,058,743,000 MeV

Kilowatt-hour (kWh) to Mega Electron Volt (MeV)

1 kWh = 825,736,420,222,677,000,000,000 Ha

Kilowatt-hour (kWh) to Hartree (Ha)

1 kWh = 36,000,000,000,000 erg

Kilowatt-hour (kWh) to Erg (erg)

1 cal = 4.184 J

Calorie (cal) to Joule (J)

1 cal = 0.00116222 Wh

Calorie (cal) to Watt-hour (Wh)

1 cal = 0.00000116222 kWh

Calorie (cal) to Kilowatt-hour (kWh)

1 cal = 0.00418400 kJ

Calorie (cal) to Kilojoule (kJ)

1 cal = 0.00000418400 MJ

Calorie (cal) to Megajoule (MJ)

1 cal = 0.00100000 kcal

Calorie (cal) to Kilocalorie (kcal)

1 cal = 26,114,473,967,543,833,000 eV

Calorie (cal) to Electron Volt (eV)

1 cal = 26,114,473,967,543.832 MeV

Calorie (cal) to Mega Electron Volt (MeV)

1 cal = 959,689,217,281,022,300 Ha

Calorie (cal) to Hartree (Ha)

1 cal = 41,840,000 erg

Calorie (cal) to Erg (erg)

Kilojoule (kJ) to Joule (J)

1 kJ = 0.277778 Wh

Kilojoule (kJ) to Watt-hour (Wh)

1 kJ = 0.000277778 kWh

Kilojoule (kJ) to Kilowatt-hour (kWh)

1 kJ = 239.006 cal

Kilojoule (kJ) to Calorie (cal)

1 kJ = 0.00100000 MJ

Kilojoule (kJ) to Megajoule (MJ)

1 kJ = 0.239006 kcal

Kilojoule (kJ) to Kilocalorie (kcal)

1 kJ = 6,241,509,074,460,763,000,000 eV

Kilojoule (kJ) to Electron Volt (eV)

1 kJ = 6,241,509,074,460,762 MeV

Kilojoule (kJ) to Mega Electron Volt (MeV)

1 kJ = 229,371,227,839,632,500,000 Ha

Kilojoule (kJ) to Hartree (Ha)

1 kJ = 10,000,000,000 erg

Kilojoule (kJ) to Erg (erg)

1 MJ = 1,000,000 J

Megajoule (MJ) to Joule (J)

1 MJ = 277.778 Wh

Megajoule (MJ) to Watt-hour (Wh)

1 MJ = 0.277778 kWh

Megajoule (MJ) to Kilowatt-hour (kWh)

1 MJ = 239,005.736 cal

Megajoule (MJ) to Calorie (cal)

1 MJ = 1,000 kJ

Megajoule (MJ) to Kilojoule (kJ)

1 MJ = 239.006 kcal

Megajoule (MJ) to Kilocalorie (kcal)

1 MJ = 6,241,509,074,460,763,000,000,000 eV

Megajoule (MJ) to Electron Volt (eV)

1 MJ = 6,241,509,074,460,762,000 MeV

Megajoule (MJ) to Mega Electron Volt (MeV)

1 MJ = 229,371,227,839,632,500,000,000 Ha

Megajoule (MJ) to Hartree (Ha)

1 MJ = 10,000,000,000,000 erg

Megajoule (MJ) to Erg (erg)

1 kcal = 4,184 J

Kilocalorie (kcal) to Joule (J)

1 kcal = 1.162 Wh

Kilocalorie (kcal) to Watt-hour (Wh)

1 kcal = 0.00116222 kWh

Kilocalorie (kcal) to Kilowatt-hour (kWh)

1 kcal = 1,000 cal

Kilocalorie (kcal) to Calorie (cal)

1 kcal = 4.184 kJ

Kilocalorie (kcal) to Kilojoule (kJ)

1 kcal = 0.00418400 MJ

Kilocalorie (kcal) to Megajoule (MJ)

1 kcal = 26,114,473,967,543,833,000,000 eV

Kilocalorie (kcal) to Electron Volt (eV)

1 kcal = 26,114,473,967,543,828 MeV

Kilocalorie (kcal) to Mega Electron Volt (MeV)

1 kcal = 959,689,217,281,022,400,000 Ha

Kilocalorie (kcal) to Hartree (Ha)

1 kcal = 41,840,000,000 erg

Kilocalorie (kcal) to Erg (erg)

1 eV = 1.60218e-19 J

Electron Volt (eV) to Joule (J)

1 eV = 4.45049e-23 Wh

Electron Volt (eV) to Watt-hour (Wh)

1 eV = 4.45049e-26 kWh

Electron Volt (eV) to Kilowatt-hour (kWh)

1 eV = 3.82929e-20 cal

Electron Volt (eV) to Calorie (cal)

1 eV = 1.60218e-22 kJ

Electron Volt (eV) to Kilojoule (kJ)

1 eV = 1.60218e-25 MJ

Electron Volt (eV) to Megajoule (MJ)

1 eV = 3.82929e-23 kcal

Electron Volt (eV) to Kilocalorie (kcal)

1 eV = 0.00000100000 MeV

Electron Volt (eV) to Mega Electron Volt (MeV)

1 eV = 0.0367493 Ha

Electron Volt (eV) to Hartree (Ha)

1 eV = 1.60218e-12 erg

Electron Volt (eV) to Erg (erg)

1 MeV = 1.60218e-13 J

Mega Electron Volt (MeV) to Joule (J)

1 MeV = 4.45049e-17 Wh

Mega Electron Volt (MeV) to Watt-hour (Wh)

1 MeV = 4.45049e-20 kWh

Mega Electron Volt (MeV) to Kilowatt-hour (kWh)

1 MeV = 3.82929e-14 cal

Mega Electron Volt (MeV) to Calorie (cal)

1 MeV = 1.60218e-16 kJ

Mega Electron Volt (MeV) to Kilojoule (kJ)

1 MeV = 1.60218e-19 MJ

Mega Electron Volt (MeV) to Megajoule (MJ)

1 MeV = 3.82929e-17 kcal

Mega Electron Volt (MeV) to Kilocalorie (kcal)

1 MeV = 1,000,000 eV

Mega Electron Volt (MeV) to Electron Volt (eV)

1 MeV = 36,749.322 Ha

Mega Electron Volt (MeV) to Hartree (Ha)

1 MeV = 0.00000160218 erg

Mega Electron Volt (MeV) to Erg (erg)

1 Ha = 4.35974e-18 J

Hartree (Ha) to Joule (J)

1 Ha = 1.21104e-21 Wh

Hartree (Ha) to Watt-hour (Wh)

1 Ha = 1.21104e-24 kWh

Hartree (Ha) to Kilowatt-hour (kWh)

1 Ha = 1.04200e-18 cal

Hartree (Ha) to Calorie (cal)

1 Ha = 4.35974e-21 kJ

Hartree (Ha) to Kilojoule (kJ)

1 Ha = 4.35974e-24 MJ

Hartree (Ha) to Megajoule (MJ)

1 Ha = 1.04200e-21 kcal

Hartree (Ha) to Kilocalorie (kcal)

1 Ha = 27.211 eV

Hartree (Ha) to Electron Volt (eV)

1 Ha = 0.0000272114 MeV

Hartree (Ha) to Mega Electron Volt (MeV)

1 Ha = 4.35974e-11 erg

Hartree (Ha) to Erg (erg)

1 erg = 1.00000e-7 J

Erg (erg) to Joule (J)

1 erg = 2.77778e-11 Wh

Erg (erg) to Watt-hour (Wh)

1 erg = 2.77778e-14 kWh

Erg (erg) to Kilowatt-hour (kWh)

1 erg = 2.39006e-8 cal

Erg (erg) to Calorie (cal)

1 erg = 1.00000e-10 kJ

Erg (erg) to Kilojoule (kJ)

1 erg = 1.00000e-13 MJ

Erg (erg) to Megajoule (MJ)

1 erg = 2.39006e-11 kcal

Erg (erg) to Kilocalorie (kcal)

1 erg = 624,150,907,446.076 eV

Erg (erg) to Electron Volt (eV)

1 erg = 624,150.907 MeV

Erg (erg) to Mega Electron Volt (MeV)

1 erg = 22,937,122,783.963 Ha

Erg (erg) to Hartree (Ha)

Energy conversion calculator supports multiple energy units including joules, calories, electron volts, and more. Convert between basic energy units, molar energy units, atomic physics units, and equivalent units with high precision.

This energy converter covers all common energy units used in physics, chemistry, and engineering. From basic joules and calories to advanced atomic units like hartrees and rydbergs, get accurate conversions for scientific calculations.

Use this comprehensive energy unit converter for laboratory work, theoretical physics calculations, and engineering applications. Supports conversion between SI units, CGS units, atomic units, and specialized energy measurements.

Popular Unit Conversions

Direct links to common conversion pages with formulas, tables, and FAQ.

kWh to JKilowatt-hour (kWh) to Joule (J)J to kWhJoule (J) to Kilowatt-hour (kWh)kWh to MJKilowatt-hour (kWh) to Megajoule (MJ)MJ to kWhMegajoule (MJ) to Kilowatt-hour (kWh)Wh to JWatt-hour (Wh) to Joule (J)J to WhJoule (J) to Watt-hour (Wh)eV to JElectron Volt (eV) to Joule (J)J to eVJoule (J) to Electron Volt (eV)kcal to kJKilocalorie (kcal) to Kilojoule (kJ)kJ to kcalKilojoule (kJ) to Kilocalorie (kcal)Ha to eVHartree (Ha) to Electron Volt (eV)eV to HaElectron Volt (eV) to Hartree (Ha)

Principles & formula sources

Energy in SI is joule (J). Practical units (kWh, cal/kcal, eV) map to J through defined factors: kWh = W·h, calories use conventional definitions, and eV uses charge/voltage relations.

We convert via J and apply ratio conversion to keep engineering and lab units consistent.

Formula & example

Formula: value_target = value_source * (source_to_J) / (target_to_J).

Example: 1 kWh = 3.6 MJ; 1 cal = 4.184 J.

Common errors & notes

Calorie ambiguity: in nutrition “Calorie” usually means kcal.
Don’t confuse power (W) with energy (J). Multiply by time when needed.
For eV, be consistent with constants when comparing literature.

Practical use cases

Energy conversions help compare battery specs, heating/cooling loads, and chemical energy outputs across J, kWh, and cal.

If you are estimating costs, convert to kWh early so pricing is applied consistently.

References / data sources

BIPM — SI Brochure (J, W, V)
NIST SP 811 — Guide for the Use of SI
CODATA — Recommended constants (eV relations)