Calculate cal to kW and cal to kWh conversions by switching between calorie energy, calorie rate, kilowatt-hours, and kilowatts.
Assumptions Assumptions
- Thermochemical calorie is used: 1 cal = 4.184 J; 1 kcal (and 1 Cal, “food Calorie”) = 4184 J.
- Rates are pure energy-per-time conversions; no efficiency or heat-loss factors are applied.
- Time base: 1 min = 60 s; 1 h = 3600 s; 1 day = 86400 s; power: 1 kW = 1000 W.
- Values are treated as steady (average) rates over the selected time unit.
When to Use This Calculator
- Converting nutrition or metabolic rates (Cal/h, kcal/min) to electrical power (W, kW).
- Relating heat-generation/absorption rates to equipment power ratings.
- HVAC, lab, or classroom problems involving energy rate conversions.
Input Definitions
- Calorie Rate — choose cal, kcal, or Cal and a time unit (s, min, h, day).
- Power — choose output in W or kW.
- Quick refs — 1 cal/s = 4.184 W; 1 kcal/s (Cal/s) = 4.184 kW; 1 Cal/h ≈ 1.162 W.
Customize This Calculator
Build your own version. Describe what you want changed, added, or compared.
- All Unit Converters
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- Cal to kWh Conversion Calculator
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Cal to kW Conversion Formula
Because a calorie measures energy and a kilowatt measures power (energy per unit time), the conversion you need depends on what you are starting with. Use the energy formula to convert calories to kilowatt-hours, and the power formula to convert a calorie rate to kilowatts.
E_{kWh} = E_{kcal} \times 0.001163
Where:
- E_kWh is the energy in kilowatt-hours (kWh)
- E_kcal is the energy in kilocalories (kcal)
- 0.001163 is the number of kilowatt-hours in one kilocalorie, equal to 4186.8 joules divided by 3,600,000 joules per kWh
P_{kW} = R_{kcal/h} \times 0.001163
Where:
- P_kW is the power in kilowatts (kW)
- R_kcal/h is the calorie rate in kilocalories per hour (kcal/h)
- 0.001163 is the kilowatts produced by a steady rate of one kilocalorie per hour, equal to 4186.8 joules divided by 3,600 seconds divided by 1,000 watts per kW
One food Calorie (Cal) equals one kilocalorie, so a Calorie value uses the same factors as a kcal value. A small calorie (cal) is one thousandth of a kilocalorie.
Common Calorie and Kilowatt Conversions
These reference values cover the most common energy and power conversions for this calculator.
| Energy input | Equals (kWh) |
|---|---|
| 1 kcal | 0.001163 kWh |
| 100 kcal | 0.1163 kWh |
| 1,000 kcal | 1.163 kWh |
| 2,000 Cal (food) | 2.326 kWh |
| 1 cal | 0.000001163 kWh |
| Rate input | Equals (kW) |
|---|---|
| 1 kcal/h | 0.001163 kW |
| 860 kcal/h | 1.000 kW |
| 1 kcal/s | 4.187 kW |
| 1 cal/s | 0.004187 kW |
Example Problems
Example 1. You want to convert 500 kcal of food energy into kilowatt-hours. Select the energy conversion type and enter 500 in the calories field with the unit set to kcal. Multiply 500 by 0.001163 to get 0.5815 kWh.
Example 2. A heater releases 2,000 kcal/h and you want the power in kilowatts. Select the power conversion type and enter 2,000 in the calorie rate field with the unit set to kcal/h. Multiply 2,000 by 0.001163 to get 2.326 kW.
Frequently Asked Questions
Can you convert calories directly to kilowatts? Not directly. A calorie is a unit of energy and a kilowatt is a unit of power, which is energy per unit of time. To reach kilowatts you need a rate such as kilocalories per hour. To convert a plain calorie amount, convert to kilowatt-hours instead.
What is the difference between kW and kWh? A kilowatt (kW) measures how fast energy is used or produced at a given moment. A kilowatt-hour (kWh) measures a total amount of energy, equal to one kilowatt sustained for one hour.
Is a food Calorie the same as a kilocalorie? Yes. The Calorie shown on nutrition labels, written with a capital C, equals one kilocalorie (1,000 small calories), so it uses the same conversion factors in this calculator.
