Energy, in simple terms, can be defined as the capacity for doing work. It can occur in kinetic, potential, electrical, chemical, nuclear, thermal, and other forms. It is classified as renewable energy and non-renewable energy. Further, in this article, we shall discuss the various units of energy.
What is the SI Unit of Energy?
Following is the table of SI unit:
| SI unit | Joules |
Interestingly, the name of this international unit is kept in honor of James Prescott Joule, a British physicist whose works contributed to the establishment of the energy concept. When we look at the unit in fundamental terms, 1-N.m is equal to 1 Joule and, in terms of SI base units it can be represented as:
| 1J=1kg(m/s)2=1kg.m2/s2 |
What is the CGS Unit Of Energy?
Following is the table of the unit in the CGS system:
| CGS unit | erg |
The erg is equal to 10-7 J. An erg is defined as the amount of the work done by the force of one dyne on one-centimeter distance.
What is the Unit Of Energy In MKS System?
Following is the table of the unit in the MKS system:
| MKS unit | Joule |
Units Of Energy List
Energy units can be preceded by various factors and there are usually different units for measuring energy. Some common units include:
- British thermal unit (BTU)
- Horsepower
- Kilowatt-hour (kWh)
- Calorie
- Electronvolts (eV)
- Hartree (the atomic unit of energy)
- Rydberg units
- Barrel of oil
Energy Conversion
Following is the table with energy conversion list:
| Unit | Joule | Calorie | BTU | Kilowatt-hour |
| Joule | 00 | 0.2390 | 0.000948 | 2.77778E-07 |
| Calorie | 4.187 | 00 | 0.00397 | 1.16279E-06 |
| BTU | 1055 | 252 | 00 | 0.000293 |
| Kilowatt-hour | 3.6E6 | 8.6E5 | 3412 | 00 |
Commercial Unit of Energy
Kilowatt-hour is the commercial unit of energy.
When large quantities of energy are expressed, the SI unit of energy becomes small. Therefore, the commercial unit is used.