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Btu (th) Inches/hour/sq. foot/°F to Btu (it) Inches/second/sq. foot/°F Converter (Btu (th)·in/(h·ft²·°F) to Btu·in/(s·ft²·°F))

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Live Conversion • ISO 80000-5:2019 Certified
1 BTU (th) inch/hour/sq. foot/°F = 0.00027759194 BTU (IT) inch/second/sq. foot/°F
1 Btu (th)·in/(h·ft²·°F) = 0.000277592 Btu·in/(s·ft²·°F) • 1 Btu·in/(s·ft²·°F) = 3602.410023 Btu (th)·in/(h·ft²·°F)
BTU (th) inch/hour/sq. foot/°F to BTU (IT) inch/second/sq. foot/°F: One BTU (th) inch/hour/sq. foot/°F is equal to 0.00027759194 Btu (it) Inches/second/sq. foot/°F.
Certified Authority Value
0.00027759
Btu·in/(s·ft²·°F)
Exact: 1 Btu·in/(s·ft²·°F) ≡ 3602.4100230762 Btu (th)·in/(h·ft²·°F)
Btu (th)·in/(h·ft²·°F)
Btu (th)·in/(h·ft²·°F)
Swap to BTU (IT) inch/second/sq. foot/°F to BTU (th) inch/hour/sq. foot/°F
Swap to BTU (IT) inch/second/sq. foot/°F to BTU (th) inch/hour/sq. foot/°F
Btu·in/(s·ft²·°F)
Btu·in/(s·ft²·°F) 0.00027759194
Quick Values:
Conversion Formula
To convert BTU (th) inch/hour/sq. foot/°F to BTU (IT) inch/second/sq. foot/°F, multiply by 0.00027759194
Btu (th)·in/(h·ft²·°F) × 0.00027759194 = Btu·in/(s·ft²·°F)

Calculation: 1 Btu (th)·in/(h·ft²·°F) × 0.00027759194 = 0.00027759194 Btu·in/(s·ft²·°F)

Common BTU (th) inch/hour/sq. foot/°F to BTU (IT) inch/second/sq. foot/°F Calculations

Quick-lookup reference table showing calculated equivalents for standard increments between BTU (th) inch/hour/sq. foot/°F (Btu (th)·in/(h·ft²·°F)) and BTU (IT) inch/second/sq. foot/°F (Btu·in/(s·ft²·°F)).

Tap any row to calculate
BTU (th) inch/hour/sq. foot/°F to BTU (IT) inch/second/sq. foot/°F: Primary Direct Table (15 Steps)
BTU (th) inch/hour/sq. foot/°F to BTU (IT) inch/second/sq. foot/°F Conversion Reference Table
Conversion & Equivalent Value Scientific Notation
0.001 Btu (th)·in/(h·ft²·°F) 2.775919 × 10⁻⁷ Btu·in/(s·ft²·°F) 2.776 × 10⁻⁷
0.01 Btu (th)·in/(h·ft²·°F) 2.775919 × 10⁻⁶ Btu·in/(s·ft²·°F) 2.776 × 10⁻⁶
0.1 Btu (th)·in/(h·ft²·°F) 2.775919 × 10⁻⁵ Btu·in/(s·ft²·°F) 2.776 × 10⁻⁵
0.5 Btu (th)·in/(h·ft²·°F) 0.000138796 Btu·in/(s·ft²·°F) 1.388 × 10⁻⁴
1 Btu (th)·in/(h·ft²·°F) 0.000277592 Btu·in/(s·ft²·°F) 2.776 × 10⁻⁴
2 Btu (th)·in/(h·ft²·°F) 0.000555184 Btu·in/(s·ft²·°F) 5.552 × 10⁻⁴
5 Btu (th)·in/(h·ft²·°F) 0.00138796 Btu·in/(s·ft²·°F) 1.388 × 10⁻³
10 Btu (th)·in/(h·ft²·°F) 0.00277592 Btu·in/(s·ft²·°F) 2.776 × 10⁻³
20 Btu (th)·in/(h·ft²·°F) 0.00555184 Btu·in/(s·ft²·°F) 5.552 × 10⁻³
25 Btu (th)·in/(h·ft²·°F) 0.0069398 Btu·in/(s·ft²·°F) 6.94 × 10⁻³
50 Btu (th)·in/(h·ft²·°F) 0.0138796 Btu·in/(s·ft²·°F) 1.388 × 10⁻²
100 Btu (th)·in/(h·ft²·°F) 0.0277592 Btu·in/(s·ft²·°F) 2.776 × 10⁻²
250 Btu (th)·in/(h·ft²·°F) 0.069398 Btu·in/(s·ft²·°F) 6.94 × 10⁻²
500 Btu (th)·in/(h·ft²·°F) 0.138796 Btu·in/(s·ft²·°F) 1.388 × 10⁻¹
1000 Btu (th)·in/(h·ft²·°F) 0.277592 Btu·in/(s·ft²·°F) 2.776 × 10⁻¹
BTU (IT) inch/second/sq. foot/°F to BTU (th) inch/hour/sq. foot/°F: Reciprocal Summary
BTU (IT) inch/second/sq. foot/°F to BTU (th) inch/hour/sq. foot/°F Conversion Reference Table
Reciprocal & Equivalent Value Scientific Notation
1 Btu·in/(s·ft²·°F) 3602.410023 Btu (th)·in/(h·ft²·°F) 3.602 × 10³
5 Btu·in/(s·ft²·°F) 18012.050115 Btu (th)·in/(h·ft²·°F) 1.801 × 10⁴
10 Btu·in/(s·ft²·°F) 36024.100231 Btu (th)·in/(h·ft²·°F) 3.602 × 10⁴
50 Btu·in/(s·ft²·°F) 180120.501154 Btu (th)·in/(h·ft²·°F) 1.801 × 10⁵
100 Btu·in/(s·ft²·°F) 360241.002308 Btu (th)·in/(h·ft²·°F) 3.602 × 10⁵
View Complete 15-Row BTU (IT) inch/second/sq. foot/°F to BTU (th) inch/hour/sq. foot/°F Table

Real-World Context & Everyday Benchmarks

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To help contextualize these units in everyday life, science, and engineering, here are verified real-world reference points for BTU (th) inch/hour/sq. foot/°F (Btu (th)·in/(h·ft²·°F)) and BTU (IT) inch/second/sq. foot/°F (Btu·in/(s·ft²·°F)):

BTU (th) inch/hour/sq. foot/°F References:

  • Stationary atmospheric dry air thermal conductivity at sea level 0.180391 Btu (th)·in/(h·ft²·°F)
  • Commercial fiberglass building insulation batt thermal conductivity 0.277525 Btu (th)·in/(h·ft²·°F)
  • Liquid drinking water thermal conductivity at room temperature 4.1629 Btu (th)·in/(h·ft²·°F)
  • Architectural structural concrete wall thermal conductivity 10.4072 Btu (th)·in/(h·ft²·°F)

BTU (IT) inch/second/sq. foot/°F References:

  • Stationary atmospheric dry air thermal conductivity at sea level 5.0E-5 Btu·in/(s·ft²·°F)
  • Commercial fiberglass building insulation batt thermal conductivity 7.7E-5 Btu·in/(s·ft²·°F)
  • Liquid drinking water thermal conductivity at room temperature 0.001156 Btu·in/(s·ft²·°F)
  • Architectural structural concrete wall thermal conductivity 0.002889 Btu·in/(s·ft²·°F)

Tap any benchmark above to automatically calculate its exact equivalent in BTU (IT) inch/second/sq. foot/°F.

ISQ Dimension: [M L T⁻³ Θ⁻¹] Coherent SI Unit: watt per meter kelvin (W/(m·K)) Thermodynamics & Heat Transfer

How to Convert BTU (th) inch/hour/sq. foot/°F to BTU (IT) inch/second/sq. foot/°F

Converting BTU (th) inch/hour/sq. foot/°F (Btu (th)·in/(h·ft²·°F)) to BTU (IT) inch/second/sq. foot/°F (Btu·in/(s·ft²·°F)) is a core calculation in Thermal Conductivity, which measures a material's intrinsic capacity to conduct and transfer heat through microscopic collisions. This calculation navigates the boundary between the International Metric System (SI) and British Imperial / US Customary engineering standards. In contemporary metrology, Imperial units are defined in terms of exact SI standards via international agreements—notably NIST SP 811 and the 1959 International Yard and Pound Agreement. Exactly 1 BTU (th) inch/hour/sq. foot/°F equals 0.000277592 BTU (IT) inch/second/sq. foot/°F, while 1 Btu·in/(s·ft²·°F) equals 3602.410023 Btu (th)·in/(h·ft²·°F).

Direct Factor1 Btu (th)·in/(h·ft²·°F) = 0.000277592 Btu·in/(s·ft²·°F)
Inverse Ratio1 Btu·in/(s·ft²·°F) = 3602.410023 Btu (th)·in/(h·ft²·°F)
Conversion ScaleMetric SI to British Imperial / US Customary Bridge
First-Principles SI Derivation ProofNIST SP 811 / ISO 80000 Compliance

Mathematical Conversion Derivation via Coherent SI Base Unit

Under the International System of Quantities (ISQ), dimensional conversion between non-SI units is rigorously resolved by bridging through the coherent SI base unit (watt per meter kelvin (W/(m·K))) without arbitrary rounding:

Vtarget=Vsource×(ksource→SIktarget→SI)V_{\text{target}} = V_{\text{source}} \times \left( \frac{k_{\text{source} \to \text{SI}}}{k_{\text{target} \to \text{SI}}} \right)
Universal Dimensional Conversion Law (ISO 80000 / NIST SP 811)
1. Source SI Bridge (ksource):1 Btu (th)·in/(h·ft²·°F) = 0.144131 watt per meter kelvin (W/(m·K))
2. Target SI Bridge (ktarget):1 Btu·in/(s·ft²·°F) = 519.2204 watt per meter kelvin (W/(m·K))
Step-by-step substitution for BTU (th) inch/hour/sq. foot/°F → BTU (IT) inch/second/sq. foot/°F:V(Btu·in/(s·ft²·°F)) = V(Btu (th)·in/(h·ft²·°F)) × ( 0.144131 / 519.2204 ) = V(Btu (th)·in/(h·ft²·°F)) × 0.000277592
Mathematical FormulaValue in BTU (IT) inch/second/sq. foot/°F = Value in BTU (th) inch/hour/sq. foot/°F × 0.00027759194Direct computational formula applied for standard conversion.
Worked Example

Converting 75 Btu (th)·in/(h·ft²·°F) yields an exact output of 0.0208194 Btu·in/(s·ft²·°F) in BTU (IT) inch/second/sq. foot/°F. Under higher industrial throughput, 10000 Btu (th)·in/(h·ft²·°F) translates to 2.775919 Btu·in/(s·ft²·°F).

Inverse check: 1 Btu·in/(s·ft²·°F) = 3602.410023 Btu (th)·in/(h·ft²·°F).

Understanding BTU (th) inch/hour/sq. foot/°F and BTU (IT) inch/second/sq. foot/°F

BTU (th) inch/hour/sq. foot/°F

Btu (th)·in/(h·ft²·°F)
Imperial / US

A BTU (th) inch/hour/sq. foot/°F (Btu (th)·in/(h·ft²·°F)) is an imperial and US customary unit for thermal conductivity.

Applications & Practical Context

In practical thermal conductivity terms, a stationary atmospheric dry air thermal conductivity at sea level equals 0.180391 Btu (th)·in/(h·ft²·°F), a commercial fiberglass building insulation batt thermal conductivity equals 0.277525 Btu (th)·in/(h·ft²·°F), a liquid drinking water thermal conductivity at room temperature equals 4.1629 Btu (th)·in/(h·ft²·°F).

Physical Setup

A physical magnitude of 1 Btu (th)·in/(h·ft²·°F) corresponds to 0.144131 W/(m·K) in standard SI measurement.

Conversion to SI Unit: watt per meter kelvin (W/(m·K))
1 Btu (th)·in/(h·ft²·°F) = 0.144131 W/(m·K)

BTU (IT) inch/second/sq. foot/°F

Btu·in/(s·ft²·°F)
Imperial / US

A BTU (IT) inch/second/sq. foot/°F (Btu·in/(s·ft²·°F)) is an imperial and US customary unit for thermal conductivity.

Applications & Practical Context

In practical thermal conductivity terms, a stationary atmospheric dry air thermal conductivity at sea level equals 5 × 10⁻⁵ Btu·in/(s·ft²·°F), a commercial fiberglass building insulation batt thermal conductivity equals 7.7 × 10⁻⁵ Btu·in/(s·ft²·°F), a liquid drinking water thermal conductivity at room temperature equals 0.001156 Btu·in/(s·ft²·°F).

Physical Setup

A physical magnitude of 1 Btu·in/(s·ft²·°F) corresponds to 519.2204 W/(m·K) in standard SI measurement.

Conversion to SI Unit: watt per meter kelvin (W/(m·K))
1 Btu·in/(s·ft²·°F) = 519.2204 W/(m·K)

Domain Metrology & Engineering Applications

Governing Law & Equation

Fourier's Law of Heat Conduction (q = -k · ∇T)

Measurement Instrumentation

Rigorously quantified in laboratory and field settings using guarded hot plate apparatus (ASTM C177), laser flash thermal diffusivity analyzers, and transient plane source (TPS) sensors.

Primary Industry Sectors

Applied across thermal interface material (TIM) development, architectural insulation manufacturing, aerospace heat shield design, and refractory ceramics under international metrology standard ISO 80000-5:2019, ASTM C177.

Institutional Metrology & Standard Authority:

Formulas, conversion coefficients, and base definitions on this page strictly adhere to the ISO 80000-5:2019, ASTM C177 and the BIPM SI Brochure (9th Edition). Governed by Fourier's Law of Heat Conduction (q = -k · ∇T) under ISO 80000 dimensional vector [M L T⁻³ Θ⁻¹].

Multi-Variable Engineering Bridge Heat Transfer & Conduction Physics

Thermal Conductivity to Heat Flux Density Bridge (W/m² • kW/m² • BTU/(h·ft²) • cal/(s·cm²))

Calculate Fourier conduction heat flux q" = k × ∇T across building envelopes and industrial heat exchangers, bridging thermal conductivity [M L T⁻³ Θ⁻¹] with heat flux density [M T⁻³].

q" = k × ∇T
Vector: [W/(m·K)] × [K/m] → [W/m²]
Live Calculated Bridge Equivalent:
1 Btu (th)·in/(h·ft²·°F) at Insulated Wall Core (20K across 0.1m = 200 K/m) = 28.8263 W/m²
Equals 0.02883 kW/m² • 9.1379 BTU/(h·ft²) • 0.0006885 cal/(s·cm²)
SI Heat Flux
28.8263
W/m²
Watts per Square Meter
Solar / Combustion
0.02883
kW/m²
Kilowatts per Square Meter
US Building Envelope
9.1379
BTU/(h·ft²)
BTU per Hour Sq. Foot
CGS Thermal
0.0006885
cal/(s·cm²)
Calories per Second Sq. Cm
Meteorology
0.04132
Ly/min
Langley per Minute
Furnace Flux
2.882628 × 10⁻⁵
MW/m²
Megawatts per Square Meter
  1. 1. Normalize Input to SI Base Unit (W/(m·K)):
    k = 1 Btu (th)·in/(h·ft²·°F) × 0.1441314 = 0.1441314 W/(m·K)
  2. 2. Apply Engineering Parameter (∇T):
    Selected condition: Insulated Wall Core (20K across 0.1m = 200 K/m) at ∇T = 200 K/m
  3. 3. Execute Governing Physical Law in SI Units:
    q" = k × ∇T = (0.1441314 W/(m·K)) × (200 K/m) = 28.82628 W/m²
  4. 4. Convert to Standard Engineering Units:
    • W/m²: 28.82628 × 1 = 28.8263 W/m² (Watts per Square Meter) • kW/m²: 28.82628 × 0.001 = 0.02883 kW/m² (Kilowatts per Square Meter) • BTU/(h·ft²): 28.82628 × 0.317 = 9.1379 BTU/(h·ft²) (BTU per Hour Sq. Foot) • cal/(s·cm²): 28.82628 × 2.3885 × 10⁻⁵ = 0.0006885 cal/(s·cm²) (Calories per Second Sq. Cm) • Ly/min: 28.82628 × 0.001433 = 0.04132 Ly/min (Langley per Minute) • MW/m²: 28.82628 × 1 × 10⁻⁶ = 2.882628 × 10⁻⁵ MW/m² (Megawatts per Square Meter)
Explore Full Heat Flux Density Converter →
Engineering Substance / Operating Standard Parameter Value (K/m) Reference State / Condition Typical Industrial & Engineering Application
Insulated Wall Core (20K across 0.1m = 200 K/m) 200 200 K/m Standard residential fiberglass/mineral wool batt
Solid Brick Masonry (25K across 0.25m = 100 K/m) 100 100 K/m Architectural structural brick veneer wall
Steam Boiler Tube Wall (100K across 0.005m = 20,000 K/m) 20000 20,000 K/m Carbon steel heat recovery steam boiler tube
CPU Copper Heat Spreader (30K across 0.002m = 15,000 K/m) 15000 15,000 K/m Semiconductor thermal interface heat spreader
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Frequently Asked Questions

There are exactly 0.00027759194 btu (it) inches/second/sq. foot/°f (Btu·in/(s·ft²·°F)) in 1 btu (th) inch/hour/sq. foot/°f (Btu (th)·in/(h·ft²·°F)). To calculate larger amounts manually, simply multiply your total number of btu (th) inches/hour/sq. foot/°f by the conversion multiplier of 0.00027759194.

The mathematical formula to convert btu (th) inches/hour/sq. foot/°f to btu (it) inches/second/sq. foot/°f is: [value] * 0.00027759194 = btu (it) inches/second/sq. foot/°f. Rather than doing the math manually, you can use our high-precision online calculator to process this exact equation instantly without rounding errors.

To perform the reverse calculation from btu (it) inches/second/sq. foot/°f back to btu (th) inches/hour/sq. foot/°f, you must divide your starting value by 0.00027759194. Our bidirectional tool automatically computes this inverse equation the moment you type into the btu (it) inch/second/sq. foot/°f input field.

1 BTU (IT) inch/second/sq. foot/°F is larger than 1 BTU (th) inch/hour/sq. foot/°F. Specifically, 1 BTU (th) inch/hour/sq. foot/°F equals 0.00027759194 btu (it) inches/second/sq. foot/°f, meaning 1 BTU (IT) inch/second/sq. foot/°F is 3602.41 times larger than 1 BTU (th) inch/hour/sq. foot/°F (a difference of 3.56 orders of magnitude). Expressing measurements in btu (th) inches/hour/sq. foot/°f requires a larger numerical value to represent the equivalent physical magnitude.

Under standard international measurement guidelines, 1 BTU (th) inch/hour/sq. foot/°F converts to 0.00027759194 btu (it) inches/second/sq. foot/°f. Precise numerical conversion factors ensure consistency across laboratory, engineering, and field data.