From joules (J)
- Joules to KilojoulesJ → kJ
- Joules to Kilowatt-hoursJ → kWh
- Joules to Thermochemical caloriesJ → cal_th
- Joules to International Table British thermal unitsJ → Btu_IT
Energy conversion family
Energy unit conversions
Energy and work are derived quantities with dimension M L² T⁻²; the coherent SI unit is the joule (J), equal to N·m or kg·m²·s⁻².
Five named units
Unit and factor reference
| Unit | Symbol | Factor to base | Relationship | Definition and variant |
|---|---|---|---|---|
| joule | J | 1 | defined | The joule is the coherent SI unit for energy, work, and amount of heat: 1 J = 1 N·m = 1 kg·m²·s⁻². The base factor is exactly 1 by the family base-unit choice. |
| kilojoule | kJ | 1000 | exact | A kilojoule is the SI decimal multiple formed with kilo: 1 kJ = 1000 J. The decimal-prefix relationship is exact. |
| kilowatt-hour | kWh | 3600000 | exact | A kilowatt-hour is the energy transferred by one kilowatt for one hour: 1 kWh = 1000 J/s × 3600 s = 3,600,000 J. Named variant: Energy unit; not kilowatt per hour. The relationship is exact. |
| thermochemical calorie | cal_th | 4.184 | defined | The thermochemical calorie, cal_th, is exactly 4.184 J. Named variant: Thermochemical calorie (cal_th); not calorie_IT, mean calorie, temperature-specific calorie, or dietary Calorie (kilocalorie). The terminating base factor is exact for the thermochemical variant. |
| International Table British thermal unit | Btu_IT | 1055.05585262 | defined | The International Table British thermal unit, Btu_IT, is exactly 1.05505585262 kJ, or 1055.05585262 J. Named variant: International Table Btu (Btu_IT); not Btu_th, mean Btu, or a temperature-specific Btu variant. The terminating base factor is exact for the International Table variant. |
Every ordered pair
All 20 energy calculators
From kilojoules (kJ)
- Kilojoules to JouleskJ → J
- Kilojoules to Kilowatt-hourskJ → kWh
- Kilojoules to Thermochemical calorieskJ → cal_th
- Kilojoules to International Table British thermal unitskJ → Btu_IT
From kilowatt-hours (kWh)
- Kilowatt-hours to JouleskWh → J
- Kilowatt-hours to KilojouleskWh → kJ
- Kilowatt-hours to Thermochemical calorieskWh → cal_th
- Kilowatt-hours to International Table British thermal unitskWh → Btu_IT
From thermochemical calories (cal_th)
- Thermochemical calories to Joulescal_th → J
- Thermochemical calories to Kilojoulescal_th → kJ
- Thermochemical calories to Kilowatt-hourscal_th → kWh
- Thermochemical calories to International Table British thermal unitscal_th → Btu_IT
From international table british thermal units (Btu_IT)
Evidence and review status
This family is machine-reviewed-pending-human. Automated checks verify structure, factor parity and source references; they do not constitute human or specialist approval.
Family assumptions and limits
- This converter treats energy as a non-negative scalar amount; it does not model signed work, heat-transfer direction, efficiency, power, or time.
- Calorie means the thermochemical calorie (cal_th), exactly 4.184 J, not the International Table calorie or dietary Calorie/kilocalorie.
- Btu means the International Table British thermal unit (Btu_IT), exactly 1055.05585262 J, not thermochemical, mean, 39 °F, 59 °F, or 60 °F variants.
Authoritative references
- The International System of Units (SI), 9th edition, version 4.01; Bureau International des Poids et Mesures; Section 2.3.4, Table 4, p. 133: energy/work/heat use joule J = kg·m²·s⁻² = N·m; Section 3, Table 7, p. 138 (kilo).; accessed 2026-08-07
- NIST Guide to the SI, Appendix B.8: Factors for Units Listed Alphabetically; National Institute of Standards and Technology; Entries 'kilowatt hour', 'calorie_th', and 'British thermal unit_IT'; footnotes 9 to 11 specify cal_th = 4.184 J exactly and Btu_IT = 1.05505585262 kJ exactly and distinguish variant names.; accessed 2026-08-07