Joule (J)
SI derived unit: one newton-meter.
What is a joule?
- Symbol
- J
- Quantity
- Energy
- Unit system
- SI
- Definition
- SI derived unit: one newton-meter.
- Exact
- Yes, the value is exact by definition
- Source
- SI Brochure, 9th edition (BIPM, 2019)
Common applications
The SI unit of energy and work. Used across physics, chemistry and engineering.
Joule in other energy units
- 1 J = 0.001 kJKilojoule
- 1 J = 0.000001 MJMegajoule
- 1 J ≈ 0.0002777777778 WhWatt-hour
- 1 J ≈ 2.777777778e-7 kWhKilowatt-hour
- 1 J ≈ 0.2390057361 calJoule to Calorie (thermochemical) converter
- 1 J ≈ 0.0002390057361 kcalKilocalorie (thermochemical)
- 1 J ≈ 0.0009478171203 BTUBritish thermal unit (IT)
- 1 J ≈ 0.7375621493 ft·lbfJoule to Foot-pound-force converter
- 1 J ≈ 6.241509074e+18 eVJoule to Electronvolt converter
- 1 J = 10000000 ergErg
Joule quick reference
| Joule | Calorie (thermochemical) | Foot-pound-force | Electronvolt |
|---|---|---|---|
| 1 J | ≈ 0.2390057361 cal | ≈ 0.7375621493 ft·lbf | ≈ 6.241509074e+18 eV |
| 10 J | ≈ 2.390057361 cal | ≈ 7.375621493 ft·lbf | ≈ 6.241509074e+19 eV |
| 100 J | ≈ 23.90057361 cal | ≈ 73.75621493 ft·lbf | ≈ 6.241509074e+20 eV |
| 1000 J | ≈ 239.0057361 cal | ≈ 737.5621493 ft·lbf | ≈ 6.241509074e+21 eV |
Where the joule fits
The next smaller energy unit is the erg (erg). 1 J = 10000000 erg, and 1 erg = 1e-7 J.
The next larger energy unit is the foot-pound-force (ft·lbf). 1 J ≈ 0.7375621493 ft·lbf, and 1 ft·lbf = 1.3558179483314004 J.
Frequently asked questions
- How many calories are in one joule?
- One joule ≈ 0.2390057361 cal (calories).
- How many foot-pounds-force are in one joule?
- One joule ≈ 0.7375621493 ft·lbf (foot-pounds-force).
- How many electronvolts are in one joule?
- One joule ≈ 6.241509074e+18 eV (electronvolts).