Convert energy units — joules, calories, kilowatt-hours, BTU, kilojoules.
| Unit | Name | Value |
|---|---|---|
| J | Joule | 4.184 |
| kJ | Kilojoule | 0.004184 |
| kcal | Kilocalorie (Cal) | 0.001 |
| kWh | Kilowatt-hour | 0.0000011622222 |
| BTU | BTU | 0.0039656512 |
Formula: Kilowatt-Hour = Calorie × 1.1622e-6
Multiply any calorie value by 1.1622e-6 to get kilowatt-hour.
Reverse: Calorie = Kilowatt-Hour × 860,400
Common calorie values — factor: 1 cal = 1.1622e-6 kWh
| Calorie (cal) | Kilowatt-Hour (kWh) | Context |
|---|---|---|
| 1 cal | 1.162e-06 kWh | 1 cal |
| 5 cal | 5.811e-06 kWh | 5 cal |
| 10 cal | 1.162e-05 kWh | Small candy |
| 50 cal | 5.811e-05 kWh | 50 cal |
| 100 cal | 0.0001162 kWh | Short walk |
| 500 cal | 0.0005811 kWh | Snack |
| 1,000 cal | 0.001162 kWh | Light meal |
| 5,000 cal | 0.005811 kWh | Meal |
| 1e+04 cal | 0.01162 kWh | Large meal |
| 5e+04 cal | 0.05811 kWh | Daily intake fraction |
| 1e+05 cal | 0.1162 kWh | 100 kcal |
| 5e+05 cal | 0.5811 kWh | 500 kcal workout |
| 1e+06 cal | 1.162 kWh | 1 Mcal |
| 1.000e+09 cal | 1,162 kWh | 1 Gcal |
| 1.000e+12 cal | 1.162e+06 kWh | 1 Tcal |
1 cal = 1.1622e-6 kWh. Memorize for instant estimates.
Use 1.1622e-6 as a quick mental multiplier.
Multiply result by 860,400 to recover the original cal value.
Reads monthly bills and compares appliance energy use in kWh.
Sizes solar systems based on kWh consumption and production estimates.
Tracks charging cost and range efficiency in kWh per 100 km.
Measures building energy consumption and identifies savings in kWh.
Plans grid capacity, demand response, and billing in kWh and MWh.
Monitors real-time appliance consumption in kWh via smart meters.
The calorie (cal) was defined in 1824 as the heat needed to raise 1 gram of water by 1°C. There are two versions: the small calorie (cal = 4.184 J) and the large calorie or kilocalorie (kcal = 4,184 J), which is the 'Calorie' used in nutrition.
The calorie remains standard in chemistry for heat of reaction measurements. In the US, food packaging uses 'Calories' (with capital C) which are actually kilocalories — a persistent source of confusion.
Interesting fact: The confusion between cal and kcal means that a food label saying '200 Calories' actually means 200 kcal = 200,000 cal = 836,800 joules. The SI unit for food energy is the kilojoule.
The kilowatt-hour (kWh) is the commercial unit of electrical energy, equal to the energy consumed by a 1,000-watt appliance in one hour (3,600,000 joules). It became standard with the growth of the electrical grid in the late 19th century.
Electricity bills worldwide are denominated in kWh. A typical household uses 300–1,000 kWh per month. An electric car uses about 15–25 kWh per 100 km. Solar panels generate 250–400 kWh per year per panel.
Interesting fact: The average price of electricity in the US is about $0.12 per kWh. One kWh can run a 100W light bulb for 10 hours, charge a smartphone about 100 times, or power a laptop for 2-3 days.
Converting calorie to kilowatt-hour is common across energy, nutrition, engineering, and science. Different sectors use different energy units — joules in physics, kcal in nutrition, kWh in electricity, and BTU in HVAC — making accurate conversion essential for cross-disciplinary work and international comparisons.
Quick reference: 5 cal = 5.8111e-6 kWh and 10 cal = 1.1622e-5 kWh. Reverse: 1 kWh = 860,400 cal. Exact factor: 1 cal = 1.1622e-6 kWh.
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.