418.4
W
0.4184
kW
1,427.584
BTU/h
418.4
J/s
418.4
W
0.4184
kW
1,427.584
BTU/h
418.4
J/s
The Calories per Second to Watts Converter converts thermal power from calories per second (cal/s) to watts (W), kilowatts (kW), and BTU/hr using the conversion factor 1 cal/s = 4.184 W. This unit appears in calorimetry, heat transfer analysis, and older thermodynamics literature.
Calories per second is a unit of thermal power that directly connects the calorie (a heat energy unit) to the concept of rate. In calorimetric experiments, heat release or absorption rates are often naturally measured in calories per second — for example, the rate at which a chemical reaction releases heat, or the rate of heat loss from a surface.
The conversion to watts is straightforward: since 1 calorie = 4.184 joules (thermochemical) and 1 watt = 1 joule per second, it follows that 1 cal/s = 4.184 J/s = 4.184 W. This makes cal/s and watts directly comparable — a cal/s is roughly 4 watts.
While the cal/s is not commonly used in modern engineering (watts being preferred), it appears regularly in several contexts: differential scanning calorimetry (DSC) instruments, food science (metabolic heat production), exercise physiology (metabolic rate), and older chemical engineering references. Understanding this conversion helps bridge historical and modern literature.
Our converter also provides BTU/hr output, useful for HVAC applications. The relationship 1 cal/s ≈ 14.286 BTU/hr connects thermal calorimetry to practical heating and cooling calculations. This three-way conversion makes the tool versatile for thermal engineering across different unit conventions.
The formulas: watts = cal/s × 4.184, kW = cal/s × 0.004184, BTU/hr = cal/s × 14.2857. These derive from 1 cal_th = 4.184 J and 1 BTU = 252 cal.
Scale reference: human resting metabolic rate ≈ 20 cal/s (84 W). Vigorous exercise ≈ 250 cal/s (1046 W). A typical stove burner ≈ 2000 cal/s (8.4 kW). A candle flame ≈ 20 cal/s (80 W).
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Resting metabolic rate ≈ 20 cal/s = 84 W
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Results
500 cal/s reaction = 2.09 kW
1 calorie per second = 4.184 watts. This follows directly from 1 cal = 4.184 J and 1 W = 1 J/s.
In calorimetry (measuring heat of reactions), exercise physiology (metabolic rate), food science, and older thermodynamics references.
1 cal/s = 3.6 kcal/hr (multiply by 3600 s/hr, divide by 1000 cal/kcal). This is useful for converting metabolic rates between time scales.
Resting: about 20 cal/s (80 W). Light activity: 40–60 cal/s. Exercise: 100–300 cal/s. Peak sprint: up to 500 cal/s.
Multiply kcal/min by 69.733 to get watts. Or convert to cal/s first (multiply by 1000/60 = 16.667), then multiply by 4.184.
No. The SI unit of power is the watt. The calorie is not part of SI, and cal/s is a derived non-SI unit. Use watts for standards-compliant work.
A calorimeter measures temperature change over time in a known mass of water. Heat rate (cal/s) = mass × specific heat × (ΔT/Δt).
cal/s uses small calories (1 cal = 4.184 J). Cal/s uses large Calories (kilocalories, 1 Cal = 4184 J). Cal/s is 1000× larger.
Multiply cal/s by 14.286. This combines the cal-to-BTU conversion (1 BTU = 252 cal) with the seconds-to-hours factor (3600).
Specific heat is typically in cal/(g·°C). To find heat transfer rate in cal/s: rate = mass flow (g/s) × specific heat × temperature difference.
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