Convert Watt per square millimetre to International table BTU per hour per square foot
Convert Watt per square millimetre (W/mm²) to International table BTU per hour per square foot (BTU(IT)/(h·ft²)) instantly and accurately.
Conversion Formula
BTU(IT)/(h·ft²) = W/mm² × 316998.3306
About Watt per square millimetre
The watt per square millimetre (W/mm²) equals exactly 10⁶ W/m². Used in high-power laser material processing - cutting, welding, and additive manufacturing - and electron beam applications. A 1 kW laser focused to 1 mm² achieves 1 W/mm². Numerically equal to MW/m². 1 W/mm² = 10⁶ W/m² = 100 W/cm².
About International table BTU per hour per square foot
The international table BTU per hour per square foot (BTU(IT)/(h·ft²)) equals 1055.05585262/(3600×0.09290304) ≈ 3.15459 W/m². The standard US heat flux unit in ASHRAE, ASTM, and building codes for thermal resistance (R-value), boiler ratings, and heat exchanger design. 1 BTU(IT)/(h·ft²) ≈ 3.15459 W/m².
Quick Reference Table
| Watt per square millimetre (W/mm²) | International table BTU per hour per square foot (BTU(IT)/(h·ft²)) |
|---|---|
| 1 W/mm² | 316998 BTU(IT)/(h·ft²) |
| 2 W/mm² | 633997 BTU(IT)/(h·ft²) |
| 5 W/mm² | 1584990 BTU(IT)/(h·ft²) |
| 10 W/mm² | 3169980 BTU(IT)/(h·ft²) |
| 25 W/mm² | 7924960 BTU(IT)/(h·ft²) |
| 50 W/mm² | 15849900 BTU(IT)/(h·ft²) |
| 100 W/mm² | 31699800 BTU(IT)/(h·ft²) |