1 J = 1 J
1 kJ = 1,000 J
1 MJ = 1,000,000 J
1 Wh = 3,600 J
1 kWh = 3,600,000 J
1 MWh = 3.6 × 10⁹ J
1 BTU ≈ 1,055.06 J
1 cal ≈ 4.184 J
1 kcal = 4,184 J
1 Mcal = 4,184,000 J
A tool for converting between common energy units such as Joule (J), kilowatt-hour (kWh), British Thermal Unit (BTU), and Calorie (cal).
This calculator allows you to convert any energy unit into others instantly. Input one value, and all others are automatically calculated. Useful in electrical, thermal, and nutritional applications.
| Unit | Full Name | Relation to Joule (J) |
|---|---|---|
| J | Joule | 1 J = 1 J |
| kJ | Kilojoule | 1 kJ = 1,000 J |
| MJ | Megajoule | 1 MJ = 1,000,000 J |
| Wh | Watt-hour | 1 Wh = 3,600 J |
| kWh | Kilowatt-hour | 1 kWh = 3,600,000 J |
| MWh | Megawatt-hour | 1 MWh = 3.6 × 10⁹ J |
| BTU | British Thermal Unit | 1 BTU ≈ 1,055.06 J |
| cal | Calorie | 1 cal ≈ 4.184 J |
| kcal | Kilocalorie | 1 kcal = 4,184 J |
| Mcal | Megacalorie | 1 Mcal = 4,184,000 J |
1 kWh = 3,600,000 J
3,600,000 ÷ 4,184 ≈ 860 kcal
30,000 kcal × 4,184 = 125,520,000 J
125,520,000 ÷ 3,600,000 ≈ 34.9 kWh
1. Power system energy analysis
2. Building energy efficiency design
3. Nutritional label interpretation
4. Engineering energy balance calculations
5. Academic learning and exams
Power represents the energy consumed or produced per unit time, measured in Watts (W), where 1 W = 1 J/s; energy represents the total accumulated amount over a period of time, measured in Joules (J). The relationship is: Energy = Power × Time. For example, a 1000 W electric heater running for 1 hour consumes 1000 W × 3600 s = 3,600,000 J = 1 kWh.
BTU (British Thermal Unit) is mainly used in HVAC and industrial thermal energy fields to represent heating or cooling capacity; Calorie is mainly used in nutrition and food fields to represent the heat content of food. Both can be converted to Joules: 1 BTU ≈ 1055.06 J, 1 cal ≈ 4.184 J.
It is commonly used for power system energy analysis (kWh to MJ conversion), building energy efficiency design (BTU to kWh conversion), nutritional label interpretation (kcal to kJ conversion), energy balance calculations in engineering thermodynamics, and academic learning and exams in physics and engineering.
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