How to Use the Energy Unit Converter
Energy is expressed in different units depending on context. Food energy uses kcal (Calories) and kJ, electricity bills use kWh, HVAC capacity uses BTU, and physics uses joules (J). Quickly switching between these units helps with diet tracking, comparing utility costs, and understanding appliance specifications.
Enter any value, select its unit, and instantly see all 7 energy unit equivalents at once.
Key Energy Conversion References
- 1 kcal (Calorie) = 4.184 kJ = 4,184 J
- 1 kWh = 3,600,000 J = 3,600 kJ ≈ 860 kcal
- 1 BTU ≈ 1,055 J ≈ 0.252 kcal
- 1 cal = 4.184 J (note: cal ≠ kcal)
A 2,000 kcal daily diet is about 8,368 kJ. A 12,000 BTU/hr AC runs at about 3,517 W. 1 kWh of electricity from a 100 W bulb requires 10 hours of operation.
Frequently Asked Questions
A lowercase calorie (cal) = 4.184 J. A Calorie (Cal or kcal) = 1,000 calories. Food labels in the US always mean Calories (kcal) when they say "calories."
1 ton of refrigeration = 12,000 BTU/hr ≈ 3.517 kW. A 2-ton unit is 24,000 BTU/hr ≈ 7 kW. Larger rooms need more tons.
1 kWh ≈ 860 kcal. A 2,000 kcal daily diet equals about 2.33 kWh — comparable to leaving a 100 W bulb on for over 23 hours.