BTU per hour square foot to milliwatt per square meter converter

Convert BTU per hour square foot to milliwatt per square meter in the Irradiance family. See a sample calculation, unit definitions, and the interactive converter.

Example conversion: 1 Btu-h-ft2

3154.59075 milliwatt per square meter

This example is calculated from the same unit registry used by the interactive converter.

Formula and unit definitions

Convert incident radiant power per unit area for optics and radiometry.

target value = source value × source factor ÷ target factor

Source unit: BTU per hour square foot (Btu-h-ft2), factor 3.15459075, offset 0.

Target unit: milliwatt per square meter (mW-m2), factor 0.001, offset 0.

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Important note

The calculation is performed locally from the listed unit definitions. Display results are rounded for readability; high-precision and regulated work should use the governing standard and appropriate significant figures.

For high-precision, regulated or safety-critical use, check the underlying standard and its required precision. Historical and approximate units are identified in their names or family descriptions.

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