Energy Converter
Convert joules, kilojoules, megajoules, calories, kilocalories, watt-hours, kilowatt-hours, BTU, foot-pounds and electronvolts.
· CalcFlow Editorial
1 kWh = 3.6 MJ
Results shown are estimates for informational purposes only. Nothing on CalcFlow is financial, tax, legal, or medical advice. Always consult a qualified professional before making important decisions.
Common Energy Conversions
| Kilowatt-hours | Megajoules | Joules | Kilojoules | Calories (thermochemical) | Kilocalories (food Calories) |
|---|---|---|---|---|---|
| 1 kWh | 3.6 | 3,600,000 | 3,600 | 860,420.65 | 860.42065 |
| 2 kWh | 7.2 | 7,200,000 | 7,200 | 1,720,841.3 | 1,720.8413 |
| 5 kWh | 18 | 18,000,000 | 18,000 | 4,302,103.3 | 4,302.1033 |
| 10 kWh | 36 | 36,000,000 | 36,000 | 8,604,206.5 | 8,604.2065 |
| 50 kWh | 180 | 180,000,000 | 180,000 | 43,021,033 | 43,021.033 |
| 100 kWh | 360 | 360,000,000 | 360,000 | 86,042,065 | 86,042.065 |
| 500 kWh | 1,800 | 1,800,000,000 | 1,800,000 | 430,210,330 | 430,210.33 |
| 1,000 kWh | 3,600 | 3,600,000,000 | 3,600,000 | 860,420,650 | 860,420.65 |
| 2,000 kWh | 7,200 | 7,200,000,000 | 7,200,000 | 1,720,841,300 | 1,720,841.3 |
Popular Energy Conversions
Formula
joules = value x unit factor (1 cal = 4.184 J, 1 Wh = 3,600 J, 1 BTU(IT) = 1,055.05585262 J, 1 eV = 1.602176634e-19 J)Understanding Energy Conversion
Energy is measured in joules in the SI system. Electricity bills use kilowatt-hours, nutrition labels use kilocalories (called Calories on food packaging), and heating equipment is often rated in BTU. The thermochemical calorie is exactly 4.184 joules, so one food Calorie (a kilocalorie) is 4,184 joules. The electronvolt, now exactly defined, is used for particles and atoms.
Tips and Best Practices
- 1One kilowatt-hour equals 3.6 megajoules, or about 3,412 BTU.
- 2A food Calorie with a capital C is a kilocalorie, or 4.184 kJ.
- 3Divide kilojoules by 4.184 to get kilocalories.
Real-World Example
A 2,000 kcal day is 2,000 x 4.184 = 8,368 kJ. Running a 1.5 kW heater for 2 hours uses 3 kWh, which is 10.8 MJ.
Common Mistakes to Avoid
- Mixing calories (cal) with kilocalories (kcal); there is a factor of 1,000.
- Confusing kilowatts (power) with kilowatt-hours (energy).
- Using a different BTU definition than the one you are comparing with; several exist.
How to Use
- Pick the unit you have in the left selector and the unit you want in the right selector.
- Type a number in either box; the other box updates instantly.
- Use the swap button to reverse the direction and Copy result to copy the answer.
Frequently Asked Questions
How many joules are in a kilocalorie?
How many BTU are in a kWh?
What is the difference between kW and kWh?
Sources: NIST SP 811 (calorie_th = 4.184 J, BTU_IT, foot-pound force); SI Brochure 2019 (elementary charge 1.602176634e-19 C, so 1 eV exact).