Convert cal/(s·cm²·°C) to Watts per Square Metre Kelvin

Formula

W/(m²·K) = cal/(s·cm²·°C) × 41840

Derivation from SI units:

• 1 cal_th/(s·cm²·°C) = 4.184 J ÷ (1 s × 10⁻⁴ m² × 1 K) = 41 840 W/(m²·K) (exact)
• The SI unit of heat transfer coefficient and thermal transmittance (U-value): heat flow (W) per square metre per kelvin

Both units are defined exactly, so the factor is exact. cal/(s·cm²·°C) definition: calorie per second square centimetre degree Celsius; Watt per Square Metre Kelvin definition: watt per square metre kelvin.

Worked examples

1. A reading of 0.001 cal/(s·cm²·°C) converts to 41.84 W/(m²·K).
   0.001 cal/(s·cm²·°C) × 41840 = 41.84 W/(m²·K)
2. A value of 0.05 cal/(s·cm²·°C) is 2092 W/(m²·K).
   0.05 cal/(s·cm²·°C) × 41840 = 2092 W/(m²·K)

Where it's used

cal/(s·cm²·°C) are used for older scientific and metallurgical literature, while watts per square metre kelvin appear in building U-values (walls, roofs, windows). Both measure heat transfer coefficient (h) and thermal transmittance (U-value), so the conversion is a fixed factor.

cal/(s·cm²·°C) to other heat transfer coefficient units

Frequently asked questions

Sources

• Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "calorie_th".
• The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 4, coherent derived units with special names.

Last reviewed: 2026-10-15. Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.