Heat Flux Density Converter

Convert heat flux density between W/m², kW/m², W/cm², calories per second per cm², and International Btu per hour per ft².

Convert instantly

Enter a value and choose the units. Your answer updates as you type.

Value

From

Result

0.001 Kilowatt per square meter (kW/m²)

Quick reference

Watt per square meter (W/m²)1 base units
Kilowatt per square meter (kW/m²)1000 base units
Watt per square centimeter (W/cm²)10000 base units
Calorie per second square centimeter (cal/(s·cm²))41840 base units
International Btu per hour square foot (Btu/(h·ft²))3.1545907450630484 base units

About the Heat Flux Density Converter

Heat flux density is the rate of heat transfer through a unit area, expressed in W/m² in SI. It is useful for furnace walls, solar collectors, electronics cooling, heat exchangers, and thermal testing. The converter uses 1 W/m² as its base and the International Table BTU, so 1 Btu/(h·ft²) is approximately 3.15459 W/m².

Convert a measured surface load instantly—for example, 1 kW/m² equals 1,000 W/m². Use the Thermal Conductivity Converter to relate flux to a material gradient, or the Heat Transfer Coefficient Converter when the boundary condition is a surface-to-fluid temperature difference.

Frequently asked questions

What is heat flux density?

It is heat-transfer power divided by area, with SI unit watt per square meter (W/m²).

How many W/m² are in 1 Btu/(h·ft²)?

One International Btu per hour per square foot equals approximately 3.15459 W/m².

How is heat flux related to conductivity?

For one-dimensional conduction, heat flux magnitude is approximately k times the temperature gradient.

Take this calculation further

Browse the converters calculators collection for more tools in this subject.

For a related calculation, use Heat Transfer Coefficient Converter to convert convective heat transfer coefficients between W/(m²·K), kW/(m²·K), W/(cm²·K), and International Btu/(h·ft²·°F). Alternatively, use Specific Heat Capacity Converter to convert specific heat capacity between J/(kg·K), kJ/(kg·K), cal/(g·°C), and International Btu/(lb·°F).

For the underlying method, read A Practical Guide to Thermal Conductivity and Insulation.