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Btus (IT)/hour/sq. foot to Calories (th)/hour/cm² Converter (Btu/(h·ft²) to cal (th)/(h·cm²))

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Live Conversion • ISO 80000-5:2019 Certified
1 BTU (IT)/hour/sq. foot = 0.27142751 Calorie (th)/hour/cm²
1 Btu/(h·ft²) = 0.271428 cal (th)/(h·cm²) • 1 cal (th)/(h·cm²) = 3.684225 Btu/(h·ft²)
BTU (IT)/hour/sq. foot to Calorie (th)/hour/cm²: One BTU (IT)/hour/sq. foot is equal to 0.27142751 Calories (th)/hour/cm².
Certified Authority Value
0.27142751
cal (th)/(h·cm²)
Exact: 1 cal (th)/(h·cm²) ≡ 3.6842249395 Btu/(h·ft²)
Btu/(h·ft²)
Btu/(h·ft²)
Swap to Calorie (th)/hour/cm² to BTU (IT)/hour/sq. foot
Swap to Calorie (th)/hour/cm² to BTU (IT)/hour/sq. foot
cal (th)/(h·cm²)
cal (th)/(h·cm²) 0.27142751
Quick Values:
Conversion Formula
To convert BTU (IT)/hour/sq. foot to Calorie (th)/hour/cm², multiply by 0.27142751
Btu/(h·ft²) × 0.27142751 = cal (th)/(h·cm²)

Calculation: 1 Btu/(h·ft²) × 0.27142751 = 0.27142751 cal (th)/(h·cm²)

Common BTU (IT)/hour/sq. foot to Calorie (th)/hour/cm² Calculations

Quick-lookup reference table showing calculated equivalents for standard increments between BTU (IT)/hour/sq. foot (Btu/(h·ft²)) and Calorie (th)/hour/cm² (cal (th)/(h·cm²)).

Tap any row to calculate
BTU (IT)/hour/sq. foot to Calorie (th)/hour/cm²: Primary Direct Table (15 Steps)
BTU (IT)/hour/sq. foot to Calorie (th)/hour/cm² Conversion Reference Table
Conversion & Equivalent Value Scientific Notation
0.001 Btu/(h·ft²) 0.000271428 cal (th)/(h·cm²) 2.714 × 10⁻⁴
0.01 Btu/(h·ft²) 0.00271428 cal (th)/(h·cm²) 2.714 × 10⁻³
0.1 Btu/(h·ft²) 0.0271428 cal (th)/(h·cm²) 2.714 × 10⁻²
0.5 Btu/(h·ft²) 0.135714 cal (th)/(h·cm²) 1.357 × 10⁻¹
1 Btu/(h·ft²) 0.271428 cal (th)/(h·cm²) 2.714 × 10⁻¹
2 Btu/(h·ft²) 0.542855 cal (th)/(h·cm²) 5.429 × 10⁻¹
5 Btu/(h·ft²) 1.357138 cal (th)/(h·cm²) 1.357 × 10⁰
10 Btu/(h·ft²) 2.714275 cal (th)/(h·cm²) 2.714 × 10⁰
20 Btu/(h·ft²) 5.42855 cal (th)/(h·cm²) 5.429 × 10⁰
25 Btu/(h·ft²) 6.785688 cal (th)/(h·cm²) 6.786 × 10⁰
50 Btu/(h·ft²) 13.571375 cal (th)/(h·cm²) 1.357 × 10¹
100 Btu/(h·ft²) 27.142751 cal (th)/(h·cm²) 2.714 × 10¹
250 Btu/(h·ft²) 67.856877 cal (th)/(h·cm²) 6.786 × 10¹
500 Btu/(h·ft²) 135.713755 cal (th)/(h·cm²) 1.357 × 10²
1000 Btu/(h·ft²) 271.42751 cal (th)/(h·cm²) 2.714 × 10²
Calorie (th)/hour/cm² to BTU (IT)/hour/sq. foot: Reciprocal Summary
Calorie (th)/hour/cm² to BTU (IT)/hour/sq. foot Conversion Reference Table
Reciprocal & Equivalent Value Scientific Notation
1 cal (th)/(h·cm²) 3.684225 Btu/(h·ft²) 3.684 × 10⁰
5 cal (th)/(h·cm²) 18.421125 Btu/(h·ft²) 1.842 × 10¹
10 cal (th)/(h·cm²) 36.842249 Btu/(h·ft²) 3.684 × 10¹
50 cal (th)/(h·cm²) 184.211247 Btu/(h·ft²) 1.842 × 10²
100 cal (th)/(h·cm²) 368.422494 Btu/(h·ft²) 3.684 × 10²
View Complete 15-Row Calorie (th)/hour/cm² to BTU (IT)/hour/sq. foot 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 (IT)/hour/sq. foot (Btu/(h·ft²)) and Calorie (th)/hour/cm² (cal (th)/(h·cm²)):

BTU (IT)/hour/sq. foot References:

  • Solar constant extraterrestrial solar irradiance at top of atmosphere 431.43 Btu/(h·ft²)
  • Clear sky direct midday summer sunlight striking sea level ground 317 Btu/(h·ft²)
  • Human body resting thermal metabolic heat radiation to room 15.8499 Btu/(h·ft²)
  • Overcast winter day diffuse solar irradiance at sea level 31.6998 Btu/(h·ft²)

Calorie (th)/hour/cm² References:

  • Solar constant extraterrestrial solar irradiance at top of atmosphere 117.1 cal (th)/(h·cm²)
  • Clear sky direct midday summer sunlight striking sea level ground 86.0421 cal (th)/(h·cm²)
  • Human body resting thermal metabolic heat radiation to room 4.3021 cal (th)/(h·cm²)
  • Overcast winter day diffuse solar irradiance at sea level 8.6042 cal (th)/(h·cm²)

Tap any benchmark above to automatically calculate its exact equivalent in Calorie (th)/hour/cm².

ISQ Dimension: [M T⁻³] Coherent SI Unit: watt per square meter (W/m²) Thermodynamics & Heat Transfer

How to Convert BTU (IT)/hour/sq. foot to Calorie (th)/hour/cm²

Converting BTU (IT)/hour/sq. foot (Btu/(h·ft²)) to Calorie (th)/hour/cm² (cal (th)/(h·cm²)) is a core calculation in Heat Flux Density, which measures the rate of thermal energy transfer radiating or conducting through a unit area per second. 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 (IT)/hour/sq. foot equals 0.271428 Calorie (th)/hour/cm², while 1 cal (th)/(h·cm²) equals 3.684225 Btu/(h·ft²).

Direct Factor1 Btu/(h·ft²) = 0.271428 cal (th)/(h·cm²)
Inverse Ratio1 cal (th)/(h·cm²) = 3.684225 Btu/(h·ft²)
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 square meter (W/m²)) 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/(h·ft²) = 3.154591 watt per square meter (W/m²)
2. Target SI Bridge (ktarget):1 cal (th)/(h·cm²) = 11.622222 watt per square meter (W/m²)
Step-by-step substitution for BTU (IT)/hour/sq. foot → Calorie (th)/hour/cm²:V(cal (th)/(h·cm²)) = V(Btu/(h·ft²)) × ( 3.154591 / 11.622222 ) = V(Btu/(h·ft²)) × 0.271428
Mathematical FormulaValue in Calorie (th)/hour/cm² = Value in BTU (IT)/hour/sq. foot × 0.27142751Direct computational formula applied for standard conversion.
Worked Example

To convert 120 BTU (IT)/hour/sq. foot (Btu/(h·ft²)) to Calorie (th)/hour/cm² (cal (th)/(h·cm²)): multiply 120 by 0.271428 to get 32.571301 cal (th)/(h·cm²). At an industrial engineering scale, 100 Btu/(h·ft²) converts to 27.142751 cal (th)/(h·cm²).

Inverse check: 1 cal (th)/(h·cm²) = 3.684225 Btu/(h·ft²).

Understanding BTU (IT)/hour/sq. foot and Calorie (th)/hour/cm²

BTU (IT)/hour/sq. foot

Btu/(h·ft²)
Imperial / US

A BTU (IT)/hour/sq. foot (Btu/(h·ft²)) is an imperial and US customary unit for heat flux density.

Applications & Practical Context

In practical heat flux density terms, a solar constant extraterrestrial solar irradiance at top of atmosphere equals 431.43 Btu/(h·ft²), a clear sky direct midday summer sunlight striking sea level ground equals 317 Btu/(h·ft²), a human body resting thermal metabolic heat radiation to room equals 15.8499 Btu/(h·ft²).

Physical Setup

A physical magnitude of 1 Btu/(h·ft²) corresponds to 3.154591 W/m² in standard SI measurement.

Conversion to SI Unit: watt per square meter (W/m²)
1 Btu/(h·ft²) = 3.154591 W/m²

Calorie (th)/hour/cm²

cal (th)/(h·cm²)
Standard Unit

A Calorie (th)/hour/cm² (cal (th)/(h·cm²)) is a recognized unit for heat flux density.

Applications & Practical Context

In practical heat flux density terms, a solar constant extraterrestrial solar irradiance at top of atmosphere equals 117.1 cal (th)/(h·cm²), a clear sky direct midday summer sunlight striking sea level ground equals 86.0421 cal (th)/(h·cm²), a human body resting thermal metabolic heat radiation to room equals 4.3021 cal (th)/(h·cm²).

Physical Setup

A physical magnitude of 1 cal (th)/(h·cm²) corresponds to 11.622222 W/m² in standard SI measurement.

Conversion to SI Unit: watt per square meter (W/m²)
1 cal (th)/(h·cm²) = 11.622222 W/m²

Domain Metrology & Engineering Applications

Governing Law & Equation

Thermal Transmission Flux (q = Q̇ / A)

Measurement Instrumentation

Rigorously quantified in laboratory and field settings using Schmidt-Boelter heat flux gauges, differential thermopile foil transducers, and calibrated Gardon radiant gauges.

Primary Industry Sectors

Applied across rocket nozzle combustion chamber analysis, fire resistance testing (ASTM E119), furnace wall heat loss auditing, and hypersonic aerothermal design under international metrology standard ISO 80000-5:2019, ASME PTC 19.3.

Institutional Metrology & Standard Authority:

Formulas, conversion coefficients, and base definitions on this page strictly adhere to the ISO 80000-5:2019, ASME PTC 19.3 and the BIPM SI Brochure (9th Edition). Governed by Thermal Transmission Flux (q = Q̇ / A) under ISO 80000 dimensional vector [M T⁻³].

Multi-Variable Engineering Bridge Thermal Radiation & Power Dissipation

Heat Flux Density to Total Thermal Power Bridge (Watts • Kilowatts • Megawatts • BTU/h • Horsepower)

Calculate total continuous heat dissipation power P = q" × A across surface barriers and exchangers, bridging heat flux density [M T⁻³] with thermal power [M L² T⁻³].

P = q" × A
Vector: [W/m²] × [m²] → [W]
Live Calculated Bridge Equivalent:
1 Btu/(h·ft²) at Industrial Hydronic Radiator Panel (8 m²) = 25.2367 W
Equals 0.02524 kW • 2.523673 × 10⁻⁵ MW • 0.03384 hp
SI Power
25.2367
W
Watts
Grid / Utility
0.02524
kW
Kilowatts
Power Plant
2.523673 × 10⁻⁵
MW
Megawatts
Mechanical Rating
0.03384
hp
Horsepower (Mechanical)
Metric Horsepower
0.03431
PS
Metric Horsepower (PS)
HVAC Thermal Rating
86.11
BTU/h
BTU per Hour
  1. 1. Normalize Input to SI Base Unit (W/m²):
    q" = 1 Btu/(h·ft²) × 3.15459083 = 3.15459083 W/m²
  2. 2. Apply Engineering Parameter (A):
    Selected condition: Industrial Hydronic Radiator Panel (8 m²) at A = 8 m²
  3. 3. Execute Governing Physical Law in SI Units:
    P = q" × A = (3.15459083 W/m²) × (8 m²) = 25.236727 W
  4. 4. Convert to Standard Engineering Units:
    • W: 25.236727 × 1 = 25.2367 W (Watts) • kW: 25.236727 × 0.001 = 0.02524 kW (Kilowatts) • MW: 25.236727 × 1 × 10⁻⁶ = 2.523673 × 10⁻⁵ MW (Megawatts) • hp: 25.236727 × 0.001341 = 0.03384 hp (Horsepower (Mechanical)) • PS: 25.236727 × 0.00136 = 0.03431 PS (Metric Horsepower (PS)) • BTU/h: 25.236727 × 3.4121 = 86.11 BTU/h (BTU per Hour)
Explore Full Power Converter →
Engineering Substance / Operating Standard Parameter Value (m²) Reference State / Condition Typical Industrial & Engineering Application
Residential Window Glazing (4 m²) 4 4.0 m² Double-pane exterior window glass aperture
Industrial Hydronic Radiator Panel (8 m²) 8 8.0 m² Convective space heating radiator surface
Shell & Tube Heat Exchanger (50 m²) 50 50.0 m² Industrial process fluid cooling bundle
Power Boiler Waterwall (200 m²) 200 200.0 m² Thermal power plant steam generator wall
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Frequently Asked Questions

There are exactly 0.27142751 calories (th)/hour/cm² (cal (th)/(h·cm²)) in 1 btu (it)/hour/sq. foot (Btu/(h·ft²)). To calculate larger amounts manually, simply multiply your total number of btus (it)/hour/sq. foot by the conversion multiplier of 0.27142751.

The mathematical formula to convert btus (it)/hour/sq. foot to calories (th)/hour/cm² is: [value] * 0.27142751 = calories (th)/hour/cm². 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 calories (th)/hour/cm² back to btus (it)/hour/sq. foot, you must divide your starting value by 0.27142751. Our bidirectional tool automatically computes this inverse equation the moment you type into the calorie (th)/hour/cm² input field.

1 Calorie (th)/hour/cm² is larger than 1 BTU (IT)/hour/sq. foot. Specifically, 1 BTU (IT)/hour/sq. foot equals 0.27142751 calories (th)/hour/cm², meaning 1 Calorie (th)/hour/cm² is 3.6842 times larger than 1 BTU (IT)/hour/sq. foot (a difference of 0.57 orders of magnitude). Expressing measurements in btus (it)/hour/sq. foot requires a larger numerical value to represent the equivalent physical magnitude.

Under standard international measurement guidelines, 1 BTU (IT)/hour/sq. foot converts to 0.27142751 calories (th)/hour/cm². Precise numerical conversion factors ensure consistency across laboratory, engineering, and field data.