What is the Watts to BTU/hr Calculator?
This tool converts electrical or thermal power expressed in watts (W) into heat output measured in British Thermal Units per hour (BTU/hr). Both units describe a rate of energy transfer, so the conversion is a simple constant multiplication. It is widely used in HVAC, heating, and cooling work to compare equipment ratings, size air conditioners, and estimate heat dissipation from electronics.
How to use it
Enter the power value in watts and the calculator instantly returns the equivalent in BTU per hour. For example, a 1,500 W space heater, server, or appliance can be quickly translated into its BTU/hr heat-load equivalent — handy when sizing ventilation or cooling capacity.
The formula explained
One watt equals 3.412142 BTU per hour, since 1 BTU ≈ 1055.06 joules and there are 3600 seconds per hour: \((3600 / 1055.06) \approx 3.412142\). The conversion is therefore:
$$\text{BTU/hr} = \text{Watts} \times 3.412142$$
Worked example
Suppose a device consumes 1,000 W. Multiply:
$$1{,}000 \times 3.412142 = 3{,}412.14 \text{ BTU/hr}$$A 2,000 W heater outputs about 6,824.28 BTU/hr.
FAQ
Is 3.412 accurate enough? The rounded factor 3.412 is fine for everyday estimates; this calculator uses 3.412142 for better precision.
Does this apply to kilowatts? Yes — multiply kilowatts by 1000 first, or use the factor 3412.142 per kW.
What about cooling vs heating? The conversion is identical; BTU/hr simply measures the rate of energy, whether added or removed.
