Energy Converter
Work & heat - joules, calories, kilowatt-hours.
Enter a value above to convert between kWh and BTU.
How to convert energy units
Energy is based on the joule. One calorie is 4.184 J - and the "Calorie" on food labels is actually a kilocalorie, equal to 4,184 J. One watt-hour is 3,600 J, so one kilowatt-hour is 3,600,000 J. One BTU is 1055.05585 J.
Worked example
One kilowatt-hour is 3,600,000 J. A 2,000-kcal daily diet is 2000 × 4184 = 8,368,000 J ≈ 2.32 kWh. One BTU is 1055.06 J.
How many joules are in a kilowatt-hour?
One kilowatt-hour equals 3,600,000 joules. One watt-hour equals 3,600 J, one food kilocalorie equals 4,184 J, one calorie equals 4.184 J, and one BTU equals 1055.05585 J.
When you'll use an energy converter
Energy conversion is useful for nutrition (kilocalories and kilojoules), electricity bills (kilowatt-hours), heating and cooling (BTU), and physics or engineering (joules, electronvolts). The table above lists your value in all 8 supported units at once.
Common energy conversions
Quick-reference rates for common energy conversions - joules, calories, kilocalories, watt-hours and BTU, one unit at a time.
| From | To |
|---|---|
| 1 kilowatt-hour (kWh) | 3,600,000 J |
| 1 kilocalorie (kcal) | 4.184 kJ |
| 1 calorie (cal) | 4.184 J |
| 1 kilojoule (kJ) | 1,000 J |
| 1 kilowatt-hour (kWh) | 3,412.1416 BTU |
| 1 BTU (BTU) | 1,055.0558 J |
| 1 kilocalorie (kcal) | 1,000 cal |
| 1 watt-hour (Wh) | 3,600 J |
| 1 kilowatt-hour (kWh) | 860.4207 kcal |
| 1 joule (J) | 0.239 cal |
| 1 kilocalorie (kcal) | 1.1622 Wh |
Frequently asked questions
How many kilocalories are in a kilowatt-hour?
One kilowatt-hour equals about 860.42 kilocalories. Because one kWh is 3,600,000 joules and one kilocalorie is 4,184 joules, dividing gives 3,600,000 / 4,184.
How do I convert kilocalories to kilojoules?
Multiply the kilocalorie value by 4.184 to get kilojoules, since one kilocalorie equals 4.184 kilojoules. For example, 100 kcal becomes 100 times 4.184, which is 418.4 kJ.
How many BTU are in a kilowatt-hour?
One kilowatt-hour equals about 3,412.14 BTU. One kWh is 3,600,000 joules and one BTU is 1055.05585 joules, so 3,600,000 divided by 1055.05585 gives roughly 3,412.14.
Is a kilocalorie bigger than a BTU?
Yes, one kilocalorie is larger than one BTU. A kilocalorie is 4,184 joules while a BTU is 1055.05585 joules, making a kilocalorie about 3.97 times the size of a BTU.
What is an electronvolt?
An electronvolt is a tiny unit of energy used in atomic and particle physics, equal to 1.602176634e-19 joules. It is the energy gained by one electron moving across a potential difference of one volt.
What is a BTU?
A BTU, or British Thermal Unit, is an imperial unit of energy equal to 1055.05585 joules. It is widely used to rate the output of furnaces, air conditioners, and other heating and cooling equipment.
Popular energy conversions
Quick links to popular energy conversions - tap any pair to open the converter ready to go.