Mechanical, thermal, electrical, particle-physics and large-scale energy units.
All factors come from the central conversion registry.
| Unit | Symbol | System | Definition |
|---|---|---|---|
| Joule | J | SI | 1 J = 1 N·m |
| Kilojoule | kJ | SI | 1 kJ = 1000 J |
| Erg | erg | CGS | 1 erg = 10⁻⁷ J |
| Electronvolt | eV | SI accepted | 1 eV = exactly 1.602176634×10⁻¹⁹ J |
| Megaelectronvolt | MeV | Scientific | 1 MeV = exactly 1.602176634×10⁻¹³ J |
| Gigaelectronvolt | GeV | Scientific | 1 GeV = exactly 1.602176634×10⁻¹⁰ J |
| Calorie | cal | Thermochemical | 1 cal = exactly 4.184 J |
| Kilocalorie | kcal | Thermochemical | 1 kcal = exactly 4184 J |
| Foot-pound | ft·lb | US customary | 1 ft·lbf ≈ 1.3558179483314004 J |
| BTU (IT) | BTU | Thermal | 1 BTU(IT) = 1055.05585262 J |
| Watt-hour | Wh | Electrical | 1 Wh = 3600 J |
| Megajoule | MJ | SI | 1 MJ = 10⁶ J |
| Kilowatt-hour | kWh | Electrical | 1 kWh = 3.6 MJ |
| Megawatt-hour | MWh | Electrical | 1 MWh = 3.6×10⁹ J |
| Ton of TNT | t TNT | Conventional | 1 ton TNT = exactly 4.184×10⁹ J |
| US Therm | therm | US customary | 1 therm = 100,000 BTU(IT) = 105,505,585.262 J |
| Quad | quad | US energy | 1 quad = 10¹⁵ BTU(IT) = 1.05505585262×10¹⁸ J |
Energy units describe the capacity to do work or transfer heat. Joules provide the SI reference while calories and watt-hours are converted through documented factors rather than context-free guesses.
The interactive calculator, reference table and indexed pair pages all read from the same conversion registry, so unit definitions and formulas stay synchronized.