Milliwatts to BTU/hour Converter
Enter a value to instantly convert between power units.
1 Milliwatt = 0.0034 BTU/hour
Key Formulas
Kilowatt → Horsepower (mech)
hp = kW × 1.34102Horsepower (mech) → Kilowatt
kW = hp × 0.7457Watt → Kilowatt
kW = W × 0.001Kilowatt → Watt
W = kW × 1000Formula
BTU/h = mW × 0.003412142Electronic component heat dissipation is rated in milliwatts but must be expressed in BTU/hour for building-level HVAC load calculations. A server with 200 components each dissipating 500 mW generates 100,000 mW = 100 W = 341.2 BTU/h — useful when sizing room-level cooling. Thermal engineers also use this conversion when calculating enclosure heat gain from small embedded electronics.
Source: NIST SP 811, Table B.8
Last reviewed: · see our methodology
Frequently Asked Questions
Real-World Examples
1,000 mW (1 W) of LED lighting = 3.41 BTU/h of heat — used in precise lighting heat gain calculations for HVAC.
1000 mW = 3.41 BTU/h
5,000 mW (5 W) of electronic control board heat dissipation = 17.06 BTU/h — relevant for sealed enclosure thermal design.
5000 mW = 17.06 BTU/h
50,000 mW (50 W) of CPU heat = 170.6 BTU/h — approximately what a modern smartphone CPU generates at peak load, in a thin device with no fan.
50000 mW = 170.6 BTU/h
100,000 mW (100 W) of server board dissipation = 341.2 BTU/h — used when totaling heat loads per rack in data center HVAC planning.
100000 mW = 341.2 BTU/h