How energy conversion works
Every energy unit has a fixed ratio to the joule. The value is first converted to joules, then into the target unit.
Common values
| Value (kWh) | Result |
|---|---|
| 0.1 kWh | 86.0421 kcal |
| 0.25 kWh | 215.105 kcal |
| 0.5 kWh | 430.21 kcal |
| 1 kWh | 860.421 kcal |
| 1.5 kWh | 1290.63 kcal |
| 2 kWh | 1720.84 kcal |
| 3 kWh | 2581.26 kcal |
| 5 kWh | 4302.1 kcal |
| 10 kWh | 8604.21 kcal |
More detail
Where each unit is used
The "Calories" on nutrition labels are actually kilocalories (kcal) — 1 kcal = 4.184 kJ. The kWh on an electricity bill measures energy delivered; 1 kWh equals about 860 kcal of heat energy. BTU is the common rating unit for air conditioners and boilers.
Everyday scale. 1 kcal = 4.184 kJ and 1 kWh = 3.6 MJ. A 2,000 kcal daily diet is about 8.4 MJ — close to what a 100 W bulb draws if left on all day.
Frequently asked questions
How many kilojoules is a food-label "Calorie"?
The "Calorie" on nutrition labels is actually a kilocalorie (kcal); 1 kcal = 4.184 kJ.
How many kcal is 1 kWh?
1 kWh = 3,600,000 J ≈ 860 kcal of heat energy — the unit your electricity bill measures usage in.
How many joules is 1 BTU?
1 BTU ≈ 1,055.06 J. Air conditioners and boilers are usually rated in BTU/h (see the power converter).
What's the difference between a calorie (cal) and a kilocalorie (kcal)?
1 kcal = 1000 cal = 4184 J. The number on a nutrition label is always in kcal, even when it's just labeled "Calories".