Convert Btu (IT)·inches per Hour per Sq. Foot per °F to Watts per Meter per Kelvin
Btu (IT)·inch per Hour per Sq. Foot per °F (Btu·in/(h·ft²·°F)) to Watt per Meter per Kelvin (W/(m·K)) 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 Btu·in/(h·ft²·°F) = 0.1442 W/(m·K)
1 Btu (IT)·inch per Hour per Sq. Foot per °F = 0.1442 Watts per Meter per Kelvin
1 Watt per Meter per Kelvin = 6.9348128 Btu (IT)·inches per Hour per Sq. Foot per °F
1 Btu·in/(h·ft²·°F) in every supported unit
Conversion chart: Btu (IT)·inch per Hour per Sq. Foot per °F to Watts per Meter per Kelvin
Conversion table
| Btu (IT)·inch per Hour per Sq. Foot per °F (Btu·in/(h·ft²·°F)) | Watt per Meter per Kelvin (W/(m·K)) |
|---|---|
| 0.01 Btu·in/(h·ft²·°F) | 0.001442 W/(m·K) |
| 0.1 Btu·in/(h·ft²·°F) | 0.01442 W/(m·K) |
| 1 Btu·in/(h·ft²·°F) | 0.1442 W/(m·K) |
| 2 Btu·in/(h·ft²·°F) | 0.2884 W/(m·K) |
| 3 Btu·in/(h·ft²·°F) | 0.4326 W/(m·K) |
| 5 Btu·in/(h·ft²·°F) | 0.721 W/(m·K) |
| 10 Btu·in/(h·ft²·°F) | 1.442 W/(m·K) |
| 20 Btu·in/(h·ft²·°F) | 2.884 W/(m·K) |
| 50 Btu·in/(h·ft²·°F) | 7.21 W/(m·K) |
| 100 Btu·in/(h·ft²·°F) | 14.42 W/(m·K) |
| 1000 Btu·in/(h·ft²·°F) | 144.2 W/(m·K) |
Btu (IT)·inch per Hour per Sq. Foot per °F (Btu·in/(h·ft²·°F))
Definition: A US customary conductivity unit scaled to inch-thick material samples instead of full feet, common for thin insulation boards and building panels.
History: A natural inch-scale variant of the foot-based Btu conductivity unit, adopted since most insulation products are only a few inches thick, not a full foot.
Current use: The most commonly printed conductivity unit on US rigid foam board and batt insulation datasheets, where the material's actual thickness is measured in inches.
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)).
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 Btu (IT)·inch per Hour per Sq. Foot per °F → Watt per Meter per Kelvin: multiply by 0.1442. For example, 1 Btu·in/(h·ft²·°F) × 0.1442 = 0.1442 W/(m·K).
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 Btu·in/(h·ft²·°F) equals 0.1442 W/(m·K). 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 Watts per Meter per Kelvin are in 1 Btu (IT)·inch per Hour per Sq. Foot per °F?
1 Btu (IT)·inch per Hour per Sq. Foot per °F (Btu·in/(h·ft²·°F)) equals exactly 0.1442 Watts per Meter per Kelvin (W/(m·K)).
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.