Where the factor comes from
Divide joules by the electron charge, 1.602 × 10⁻¹⁹. Useful when a photoelectric or Bohr-model answer comes out in joules and the options are in eV.
J to eV table
| J | eV |
|---|---|
| 1 J | 6.242 × 1018 eV |
| 2 J | 1.248 × 1019 eV |
| 5 J | 3.121 × 1019 eV |
| 10 J | 6.242 × 1019 eV |
| 25 J | 1.56 × 1020 eV |
| 50 J | 3.121 × 1020 eV |
| 100 J | 6.242 × 1020 eV |
| 1,000 J | 6.242 × 1021 eV |
Other unit conversions
| Conversion | Value |
|---|---|
| Electron volt to joule | 1 eV = 1.602 × 10−19 J |
| Joule to electron volt | 1 J = 6.242 × 1018 eV |
| Calorie to joule | 1 cal = 4.184 J |
| Kilowatt hour to joule | 1 kWh = 3.6 × 106 J |
| Erg to joule | 1 erg = 10−7 J |
| Litre atmosphere to joule | 1 L atm = 101.325 J |
| Atomic mass unit to mega electron volt | 1 u = 931.494 MeV |
| Atomic mass unit to kilogram | 1 u = 1.661 × 10−27 kg |
| Atmosphere to pascal | 1 atm = 101,325 Pa |
| Atmosphere to bar | 1 atm = 1.01325 bar |
| Atmosphere to millimetre of mercury | 1 atm = 760 mmHg |
| Bar to pascal | 1 bar = 100,000 Pa |
| Angstrom to metre | 1 Å = 10−10 m |
| Angstrom to nanometre | 1 Å = 0.1 nm |
| Nanometre to metre | 1 nm = 10−9 m |
| Fermi to metre | 1 fm = 10−15 m |
| Light year to metre | 1 ly = 9.461 × 1015 m |
| Astronomical unit to kilometre | 1 AU = 1.496 × 108 km |
| Km per hour to metre per second | 1 km/h = 0.277778 m/s |
| Metre per second to km per hour | 1 m/s = 3.6 km/h |
| Dyne to newton | 1 dyn = 10−5 N |
| Kilogram weight to newton | 1 kgf = 9.8 N |
| Horsepower to watt | 1 hp = 746 W |
| Gauss to tesla | 1 G = 10−4 T |
| Degree to radian | 1 ° = 0.0174533 rad |
| Radian to degree | 1 rad = 57.2958 ° |
| Celsius to kelvin | Add 273.15 (most JEE and NEET questions use 273). A change of 1 °C is the same as a change of 1 K. |
| Kelvin to Celsius | Subtract 273.15. Absolute zero, 0 K, is −273.15 °C. |
| Celsius to Fahrenheit | Use C/5 = (F − 32)/9. Water freezes at 32 °F and boils at 212 °F. −40 °C is also −40 °F. |
| Fahrenheit to Celsius | Subtract 32, then multiply by 5/9. Body temperature 98.6 °F is 37 °C. |
Questions students ask
What is 1 J in eV?
1 J = 6.242 × 10¹⁸ eV. Divide joules by the electron charge, 1.602 × 10⁻¹⁹. Useful when a photoelectric or Bohr-model answer comes out in joules and the options are in eV.
What is the formula to convert J to eV?
eV = J × 6.242 × 10¹⁸.
How do you convert eV back to J?
Use the reverse conversion: 1 eV = 1.602 × 10⁻¹⁹ J.