Convert thermal conductivity units — W/(m·K), BTU/(h·ft·°F), cal/(s·cm·°C) and more.
| Unit | Name | Value |
|---|---|---|
| kW/(m·K) | Kilowatt/(Meter·Kelvin) | 0.001 |
| BTU/(h·ft·°F) | BTU/(Hour·Foot·°F) | 0.57779087 |
| cal/(s·cm·°C) | Calorie/(Second·cm·°C) | 0.002388459 |
| kcal/(h·m·°C) | Kilocalorie/(Hour·m·°C) | 0.85984523 |
Formula: cal/(s·cm·K) = W/(m·K) × 0.002388
Multiply any W/(m·K) value by 0.002388 to get cal/(s·cm·K).
Reverse: W/(m·K) = cal/(s·cm·K) × 418.7
Copper reference: 401 W/(m·K) = 0.9578 cal/(s·cm·K)
Factor: 1 W/(m·K) = 0.002388 cal/(s·cm·K)
| W/(m·K) (W/(m·K)) | cal/(s·cm·K) (cal/(s·cm·K)) | Material |
|---|---|---|
| 2200 W/(m·K) | 5.255 cal/(s·cm·K) | Diamond |
| 429 W/(m·K) | 1.025 cal/(s·cm·K) | Silver |
| 401 W/(m·K) | 0.9578 cal/(s·cm·K) | Copper |
| 318 W/(m·K) | 0.7595 cal/(s·cm·K) | Gold |
| 237 W/(m·K) | 0.5661 cal/(s·cm·K) | Aluminum |
| 52 W/(m·K) | 0.1242 cal/(s·cm·K) | Cast iron |
| 50 W/(m·K) | 0.1194 cal/(s·cm·K) | Steel (carbon) |
| 2.5 W/(m·K) | 0.005971 cal/(s·cm·K) | Marble |
| 1.7 W/(m·K) | 0.00406 cal/(s·cm·K) | Concrete |
| 1 W/(m·K) | 0.002388 cal/(s·cm·K) | Glass |
| 0.6 W/(m·K) | 0.001433 cal/(s·cm·K) | Water (20°C) |
| 0.17 W/(m·K) | 0.000406 cal/(s·cm·K) | Wood (oak) |
| 0.04 W/(m·K) | 9.554e-05 cal/(s·cm·K) | Fiberglass batt |
| 0.026 W/(m·K) | 6.210e-05 cal/(s·cm·K) | Air (25°C) |
| 0.015 W/(m·K) | 3.583e-05 cal/(s·cm·K) | Aerogel |
W/(m·K) ÷ 418.68 = cal/(s·cm·K).
418.68 W/(m·K) = 1 cal/(s·cm·K). 401 W/(m·K) = 0.958 cal/(s·cm·K) (copper).
cal/(s·cm·K) × 418.68 = W/(m·K).
Specifies insulation and wall assembly thermal conductivity in W/(m·K) for energy compliance calculations.
Uses BTU/(h·ft·°F) for US building code compliance and W/(m·K) for metric heat transfer calculations.
Compares thermal conductivity of metals, polymers, and composites in W/(m·K) for thermal management design.
Selects thermal interface materials and heatsinks using conductivity data in W/(m·K).
Designs heat exchangers using shell and tube thermal conductivity specifications in W/(m·K).
Measures and reports thermal conductivity of novel materials (graphene, CNTs, aerogels) in W/(m·K) or kW/(m·K).
Watt per meter per kelvin (W/(m·K)) is the SI unit of thermal conductivity. It measures the rate of heat transfer through a material of 1 meter thickness per kelvin of temperature difference per unit area. It was formally defined with the SI system in 1960.
W/(m·K) is universally used in engineering and science for specifying material thermal properties. Key values: air = 0.026 W/(m·K); water = 0.6 W/(m·K); glass = 1.0 W/(m·K); concrete = 1.7 W/(m·K); steel = 50 W/(m·K); copper = 401 W/(m·K); diamond = 2,200 W/(m·K).
Interesting fact: Diamond has the highest thermal conductivity of any natural material at about 2,200 W/(m·K) — nearly 6× that of copper and 85,000× that of air. This is why diamond heatsinks are used in high-power laser diodes and some semiconductor devices.
Calorie per second per centimeter per kelvin (cal/(s·cm·K)) is the CGS unit of thermal conductivity, equal to 418.68 W/(m·K). It was the standard in pre-SI physics and chemistry literature.
Cal/(s·cm·K) appears in older scientific handbooks and classic thermodynamics texts. Copper in CGS = 0.923 cal/(s·cm·K); iron = 0.179 cal/(s·cm·K); water = 0.00143 cal/(s·cm·K). The unit is rarely used in modern practice.
Interesting fact: The CGS unit cal/(s·cm·K) is 418.68× larger than W/(m·K) — so most materials have very small values in CGS. Water at 0.00143 cal/(s·cm·K) demonstrates why the CGS unit became impractical for most engineering applications.
Thermal conductivity measures how readily a material conducts heat. The SI unit W/(m·K) is universal in science; US building codes use BTU/(h·ft·°F); older European engineering uses kcal/(h·m·°C); CGS physics uses cal/(s·cm·K). Key anchors: air 0.026 W/(m·K), glass 1.0, steel 50, copper 401, diamond 2,200.
Exact factor: 1 W/(m·K) = 0.002388 cal/(s·cm·K). Reverse: 1 cal/(s·cm·K) = 418.7 W/(m·K).
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.