Heat Flux Converter

Convert heat flux units including watts per square meter, kilowatts per square meter, BTU per hour-square foot, calories per second-square centimeter, watts per square inch, and more.

Convert Heat Flux

1 watt per square meter = 0.317 BTU per hour-square foot
Your converted heat flux result will appear here.

Common heat flux conversions

W/m² to BTU/hr-ft²:
1 W/m² = 0.317 BTU/(hr·ft²)

BTU/hr-ft² to W/m²:
1 BTU/(hr·ft²) = 3.15459 W/m²

kW/m² to W/m²:
1 kW/m² = 1,000 W/m²

cal/(s·cm²) to W/m²:
1 cal/(s·cm²) = 41,840 W/m²

Where heat flux conversions are used

Heat flux conversions are useful for heat exchangers, insulation design, electronics cooling, furnace walls, solar radiation, thermal protection systems, HVAC surfaces, boilers, and process heat transfer.

Use this converter when comparing SI, U.S. customary, and CGS heat flux units.

What your heat flux result means

Your result shows the entered heat flux converted from the starting unit into the selected ending unit. The calculator also shows the conversion rate used so you can verify the calculation.

For engineering and thermal design, make sure the heat flux unit matches your heat transfer equation, material data, surface area calculation, equipment rating, or thermal model.

Heat flux converter tips

Frequently asked questions

What is heat flux?

Heat flux is the heat transfer rate per unit surface area.

What is the SI unit of heat flux?

The SI unit of heat flux is watts per square meter, abbreviated as W/m².

Is heat flux the same as heat transfer rate?

No. Heat transfer rate is total heat per time, while heat flux is heat transfer rate divided by area.

How many W/m² are in one BTU/(hr·ft²)?

One BTU per hour-square foot equals approximately 3.15459 W/m².

Can I convert negative heat flux values?

This converter is designed for heat flux magnitude conversions, so it uses non-negative values.