Convert International table BTU per hour per square inch to Watt per square millimetre

Convert International table BTU per hour per square inch (BTU(IT)/(h·in²)) to Watt per square millimetre (W/mm²) instantly and accurately.

International table BTU per hour per square inch (BTU(IT)/(h·in²))
Watt per square millimetre (W/mm²)

Conversion Formula

W/mm² = BTU(IT)/(h·in²) × 0.0004542610673

About International table BTU per hour per square inch

The international table BTU per hour per square inch (BTU(IT)/(h·in²)) equals 1055.05585262/(3600×6.4516×10⁻⁴) ≈ 454.26 W/m². Used for high heat flux applications such as electronic component cooling, jet engine combustor walls, and nuclear fuel assembly design in US customary units. 1 BTU(IT)/(h·in²) ≈ 454.26 W/m².

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.

Quick Reference Table

International table BTU per hour per square inch (BTU(IT)/(h·in²))Watt per square millimetre (W/mm²)
1 BTU(IT)/(h·in²)0.000454261 W/mm²
2 BTU(IT)/(h·in²)0.000908522 W/mm²
5 BTU(IT)/(h·in²)0.00227131 W/mm²
10 BTU(IT)/(h·in²)0.00454261 W/mm²
25 BTU(IT)/(h·in²)0.0113565 W/mm²
50 BTU(IT)/(h·in²)0.0227131 W/mm²
100 BTU(IT)/(h·in²)0.0454261 W/mm²

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