Convert Watts per Meter per Kelvin to Btu (IT)·feet per Hour per Sq. Foot per °F
Watt per Meter per Kelvin (W/(m·K)) to Btu (IT)·foot per Hour per Sq. Foot per °F (Btu·ft/(h·ft²·°F)) thermal conductivity conversion — enter any value below to get an instant result, or use the table for common values.
Results from this calculator are estimates provided for general informational purposes only, based on formulas, rates, and standards commonly accepted as of 2026. Figures may differ slightly from other calculators or professional sources due to rounding methods, differing assumptions, or regional regulations, and rules may change over time. Always consult a qualified professional — such as a financial advisor, healthcare provider, or other relevant specialist — before making decisions based on these results.
Result
1 W/(m·K) = 0.57780089 Btu·ft/(h·ft²·°F)
1 Watt per Meter per Kelvin = 0.57780089 Btu (IT)·feet per Hour per Sq. Foot per °F
1 Btu (IT)·foot per Hour per Sq. Foot per °F = 1.7307 Watts per Meter per Kelvin
1 W/(m·K) in every supported unit
Conversion chart: Watt per Meter per Kelvin to Btu (IT)·feet per Hour per Sq. Foot per °F
Conversion table
| Watt per Meter per Kelvin (W/(m·K)) | Btu (IT)·foot per Hour per Sq. Foot per °F (Btu·ft/(h·ft²·°F)) |
|---|---|
| 0.01 W/(m·K) | 0.0057780089 Btu·ft/(h·ft²·°F) |
| 0.1 W/(m·K) | 0.057780089 Btu·ft/(h·ft²·°F) |
| 1 W/(m·K) | 0.57780089 Btu·ft/(h·ft²·°F) |
| 2 W/(m·K) | 1.1556018 Btu·ft/(h·ft²·°F) |
| 3 W/(m·K) | 1.7334027 Btu·ft/(h·ft²·°F) |
| 5 W/(m·K) | 2.8890044 Btu·ft/(h·ft²·°F) |
| 10 W/(m·K) | 5.7780089 Btu·ft/(h·ft²·°F) |
| 20 W/(m·K) | 11.556018 Btu·ft/(h·ft²·°F) |
| 50 W/(m·K) | 28.890044 Btu·ft/(h·ft²·°F) |
| 100 W/(m·K) | 57.780089 Btu·ft/(h·ft²·°F) |
| 1000 W/(m·K) | 577.80089 Btu·ft/(h·ft²·°F) |
Watt per Meter per Kelvin (W/(m·K))
Definition: The SI derived unit of thermal conductivity — the watts of heat power that flow through one meter of a material's thickness, per square meter of cross-sectional area, per kelvin of temperature difference.
History: Formed directly from the watt, meter, and kelvin once all three SI base and derived units were standardized, giving materials scientists a single coherent conductivity unit for comparing insulators and conductors alike.
Current use: The standard unit in materials science, building physics, and mechanical engineering worldwide for rating how well or poorly a material conducts heat, from aerogel insulation (around 0.02 W/(m·K)) to solid copper (around 400 W/(m·K)).
Btu (IT)·foot per Hour per Sq. Foot per °F (Btu·ft/(h·ft²·°F))
Definition: The standard US customary thermal conductivity unit — Btu of heat energy conducted through a one-foot material thickness, per square foot of area, per hour, per degree Fahrenheit of temperature difference.
History: Built from the foot, hour, square foot, and Fahrenheit degree, all standard US construction measurements, giving American building engineers a conductivity unit matching everyday design calculations.
Current use: The standard "k-value" unit on US building material and insulation datasheets, forming the basis for the R-value ratings used throughout US residential and commercial construction.
Supported Units
| Unit | Symbol | In W/(m·K) |
|---|---|---|
| Watt per Meter per Kelvin | W/(m·K) | 1 W/(m·K) |
| Watt per Centimeter per °C | W/(cm·°C) | 100 W/(m·K) |
| Kilowatt per Meter per Kelvin | kW/(m·K) | 1000 W/(m·K) |
| Calorie (IT) per Second per Centimeter per °C | cal/(s·cm·°C) | 418.68 W/(m·K) |
| Kilocalorie (IT) per Hour per Meter per °C | kcal/(h·m·°C) | 1.163 W/(m·K) |
| Btu (IT)·inch per Second per Sq. Foot per °F | Btu·in/(s·ft²·°F) | 519.22 W/(m·K) |
| Btu (IT)·foot per Hour per Sq. Foot per °F | Btu·ft/(h·ft²·°F) | 1.7307 W/(m·K) |
| Btu (IT)·inch per Hour per Sq. Foot per °F | Btu·in/(h·ft²·°F) | 0.1442 W/(m·K) |
About These Parameters
- Value
- The thermal conductivity value you want to convert, expressed in the "From" unit. Accepts decimals.
- From Unit
- The unit your input value is currently measured in — the SI W/(m·K), or a US insulation datasheet's Btu·in/(h·ft²·°F) k-value.
- To Unit
- The conductivity unit you want the result converted into. Use the swap button to flip From and To instantly.
How Thermal Conductivity Conversion Works
The Formula
Every unit here is defined by a fixed multiplier relative to watts per meter per kelvin. To convert a value from one unit to another:
result = value × (factor of "From" unit ÷ factor of "To" unit)
For Watt per Meter per Kelvin → Btu (IT)·foot per Hour per Sq. Foot per °F: multiply by 0.57780089. For example, 1 W/(m·K) × 0.57780089 = 0.57780089 Btu·ft/(h·ft²·°F).
Conductivity (k) vs. Resistance (R)
Thermal conductivity (this page) is a property of the material itself, independent of how thick a piece of it you have. R-value, printed on US insulation packaging, is the inverse relationship scaled by an actual thickness — a thicker layer of the same material has a higher R-value even though its conductivity k hasn't changed. That's why doubling a wall's insulation thickness roughly doubles its R-value, but has no effect at all on the insulation material's underlying k-value in W/(m·K) or Btu·in/(h·ft²·°F).
Conductors vs. Insulators
Thermal conductivity spans an enormous range: solid copper conducts heat at roughly 400 W/(m·K), while modern aerogel insulation can be as low as 0.015 W/(m·K) — a difference of over 25,000 times. Materials engineers reach for this converter constantly when comparing candidate materials sourced from different countries' datasheets, since the same underlying physical property is reported in wildly different-looking numbers depending on the unit convention used.
Example
A material with a conductivity of 1 W/(m·K) equals 0.57780089 Btu·ft/(h·ft²·°F). For scale, common fiberglass batt insulation sits around 0.04 W/(m·K), while structural concrete is roughly 1.7 W/(m·K) — over 40 times more conductive, which is why concrete alone provides negligible insulation value.
Frequently Asked Questions
How many Btu (IT)·feet per Hour per Sq. Foot per °F are in 1 Watt per Meter per Kelvin?
1 Watt per Meter per Kelvin (W/(m·K)) equals exactly 0.57780089 Btu (IT)·feet per Hour per Sq. Foot per °F (Btu·ft/(h·ft²·°F)).
Why does US insulation use inches instead of feet for its k-value?
Most rigid foam and batt insulation products are only a few inches thick, so measuring conductivity per inch of thickness keeps the resulting numbers in a convenient, easy-to-compare range rather than the smaller decimals a per-foot figure would produce for the same material.
Does thermal conductivity change with temperature?
Yes, for most materials conductivity varies somewhat with temperature (and for some materials, quite significantly). The conversion factors on this page relate different UNITS for the same measured value; they don't account for how a material's own conductivity might shift between measurement conditions.
How accurate are these conversions?
Every conversion factor used here is the exact, internationally recognized relationship between the underlying energy, length, area, and temperature units — results are limited only by floating-point display precision, not by rounded conversion constants.