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: kcal/(h·m·°C) = W/(m·K) × 0.8598
Multiply any W/(m·K) value by 0.8598 to get kcal/(h·m·°C).
Reverse: W/(m·K) = kcal/(h·m·°C) × 1.163
Copper reference: 401 W/(m·K) = 344.8 kcal/(h·m·°C)
Factor: 1 W/(m·K) = 0.8598 kcal/(h·m·°C)
| W/(m·K) (W/(m·K)) | kcal/(h·m·°C) (kcal/(h·m·°C)) | Material |
|---|---|---|
| 2200 W/(m·K) | 1892 kcal/(h·m·°C) | Diamond |
| 429 W/(m·K) | 368.9 kcal/(h·m·°C) | Silver |
| 401 W/(m·K) | 344.8 kcal/(h·m·°C) | Copper |
| 318 W/(m·K) | 273.4 kcal/(h·m·°C) | Gold |
| 237 W/(m·K) | 203.8 kcal/(h·m·°C) | Aluminum |
| 52 W/(m·K) | 44.71 kcal/(h·m·°C) | Cast iron |
| 50 W/(m·K) | 42.99 kcal/(h·m·°C) | Steel (carbon) |
| 2.5 W/(m·K) | 2.15 kcal/(h·m·°C) | Marble |
| 1.7 W/(m·K) | 1.462 kcal/(h·m·°C) | Concrete |
| 1 W/(m·K) | 0.8598 kcal/(h·m·°C) | Glass |
| 0.6 W/(m·K) | 0.5159 kcal/(h·m·°C) | Water (20°C) |
| 0.17 W/(m·K) | 0.1462 kcal/(h·m·°C) | Wood (oak) |
| 0.04 W/(m·K) | 0.03439 kcal/(h·m·°C) | Fiberglass batt |
| 0.026 W/(m·K) | 0.02236 kcal/(h·m·°C) | Air (25°C) |
| 0.015 W/(m·K) | 0.0129 kcal/(h·m·°C) | Aerogel |
W/(m·K) × 0.8598 = kcal/(h·m·°C). Round to × 0.860.
1.163 W/(m·K) = 1 kcal/(h·m·°C). 50 W/(m·K) = 43 kcal/(h·m·°C).
kcal/(h·m·°C) × 1.163 = 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.
Kilocalorie per hour per meter per degree Celsius (kcal/(h·m·°C)) equals 1.163 W/(m·K). It was used in older European engineering texts and some industrial specifications, particularly in countries using kcal for thermal calculations before SI adoption.
kcal/(h·m·°C) appears in older continental European building physics, heat exchanger design manuals, and some Russian and Eastern European engineering standards. Steel ≈ 43 kcal/(h·m·°C); concrete ≈ 1.46 kcal/(h·m·°C); air ≈ 0.022 kcal/(h·m·°C).
Interesting fact: The kcal was the standard energy unit in continental European engineering before SI adoption in the 1970s–1980s. Many countries' building codes still include kcal-based thermal conductivity values in older editions, requiring conversion when working with modern SI specifications.
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) = 0.8598 kcal/(h·m·°C). Reverse: 1 kcal/(h·m·°C) = 1.163 W/(m·K).
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.