About this converter
Energy measures the capacity to do work or transfer heat. Joule (J) is the SI unit, 1 kilowatt-hour equals exactly 3,600,000 J, 1 watt-hour equals 3,600 J, and 1 BTU (IT) is about 1,055.06 J.
This converter supports mechanical, thermal, electrical, food-energy, particle-physics, and CGS energy units. Thermodynamics students, HVAC technicians, energy analysts, electricians, physics instructors, and mechanical engineers use energy conversions for utility bills, heat loads, lab data, and work calculations.
How to Use This Converter
- Enter the energy value.
- Select the source unit from the From menu.
- Select the target unit from the To menu.
- Read the converted result and formula line.
- Use Swap to reverse the selected units.
Units Covered
| Unit | Symbol | Common Use |
|---|---|---|
| Joule | J | SI energy, work, heat, and physics calculations. |
| Kilojoule | kJ | Thermodynamics, nutrition, chemistry, and engineering data. |
| Thermochemical calorie | cal th | Heat measurements and chemistry references. |
| IT calorie | cal IT | International steam table calorie references. |
| Kilocalorie | kcal | Food energy, nutrition, and thermal calculations. |
| Watt-hour | Wh | Battery capacity and small electrical energy use. |
| Kilowatt-hour | kWh | Utility bills, appliance energy, and electrical consumption. |
| BTU IT | BTU | HVAC heating and cooling, boilers, and heat transfer. |
| Electronvolt | eV | Atomic, semiconductor, photon, and particle energy. |
| Erg | erg | CGS physics and legacy scientific data. |
| Foot-pound | ft-lb | Mechanical work in imperial engineering references. |
| US therm | therm | Natural gas billing and large heat-energy quantities. |
kWh to Joules Conversion Table
| From | To |
|---|---|
| 0.001 kWh | 3,600 J |
| 0.01 kWh | 36,000 J |
| 0.1 kWh | 360,000 J |
| 0.5 kWh | 1,800,000 J |
| 1 kWh | 3,600,000 J |
| 2 kWh | 7,200,000 J |
| 5 kWh | 18,000,000 J |
| 10 kWh | 36,000,000 J |
| 25 kWh | 90,000,000 J |
| 100 kWh | 360,000,000 J |
How to Convert kWh to Joules
Kilowatt-hours to joules
For example, 2.5 kWh x 3,600,000 = 9,000,000 J.
Joules to kilowatt-hours
For example, 18,000,000 J / 3,600,000 = 5 kWh.
When You Need to Convert Energy
Electrical energy bills use kWh, while physics and engineering equations use joules. A 1.5 kWh appliance cycle equals 5,400,000 J, which helps compare household energy use with technical calculations.
HVAC and heat-transfer work often mixes BTU, joules, and kilojoules. A 10,000 BTU heat load is about 10,550,600 J, useful when comparing equipment ratings with SI thermal models.
Physics and electronics work may use electronvolts for small energy scales. A visible-light photon around 2 eV is only about 3.204 x 10^-19 J, so unit choice matters when numbers are extremely small.