Cal to Kw Conversion Calculator

Enter a calorie rate or power to convert between Cal/kcal/cal per time and kW or W.

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.

Cal to kW Formula

The following formulas convert a calorie rate to power in kilowatts and back, using Joules per calorie and seconds per time unit.

\mathrm{kW} = \frac{r \cdot J_u}{t_s \cdot 1000}

r = \frac{\mathrm{kW} \cdot 1000 \cdot t_s}{J_u}

Small calorie: 1 cal = 4.184 J (so J_u = 4.184 J/cal).
Kilocalorie/food Calorie: 1 kcal = 1 Cal = 4184 J (so J_u = 4184 J/kcal or J/Cal).
Time bases: t_s = 1 (s), 60 (min), 3600 (h), 86400 (day).
Power: 1 kW = 1000 W.

How do you convert a Calorie rate to kW? Multiply the rate by Joules per calorie (4.184 for cal or 4184 for kcal/Cal), divide by the seconds in the chosen time unit, then divide by 1000 to get kW.

How do you convert kW to a Calorie rate? Multiply kW by 1000 to get W, multiply by seconds in the target time unit, then divide by Joules per calorie for the chosen Calorie unit.

Cal/h to kW Conversion Table

Food Calories per Hour (Cal/h) to kW
Cal/h	kW
1	0.001
5	0.006
10	0.012
25	0.029
50	0.058
75	0.087
100	0.116
125	0.145
150	0.174
175	0.203
200	0.232
250	0.291
300	0.349
350	0.407
400	0.465
500	0.581
750	0.872
1000	1.162
2000	2.324
* 1 Cal/h = 4184 J / 3600 s ≈ 1.16222 W = 0.00116222 kW.

Example Problem

Convert 250 Cal/h to kW.

Use the formula: kW = (Cal/h × 4184) ÷ (3600 × 1000).

kW = 250 × 4184 ÷ 3,600,000 = 0.2906 kW

Cal to kW Formula

Cal/h to kW Conversion Table

Example Problem