Convert Watts per Square Inch to Foot Pounds per Minute per Square Foot
Watt per Square Inch (W/in²) to Foot Pound per Minute per Square Foot (ft·lb/(min·ft²)) heat flux density 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/in² = 6373.368 ft·lb/(min·ft²)
1 Watt per Square Inch = 6373.368 Foot Pounds per Minute per Square Foot
1 Foot Pound per Minute per Square Foot = 0.00015690291 Watts per Square Inch
1 W/in² in every supported unit
Conversion chart: Watt per Square Inch to Foot Pounds per Minute per Square Foot
Conversion table
| Watt per Square Inch (W/in²) | Foot Pound per Minute per Square Foot (ft·lb/(min·ft²)) |
|---|---|
| 0.01 W/in² | 63.73368 ft·lb/(min·ft²) |
| 0.1 W/in² | 637.3368 ft·lb/(min·ft²) |
| 1 W/in² | 6373.368 ft·lb/(min·ft²) |
| 2 W/in² | 12746.736 ft·lb/(min·ft²) |
| 3 W/in² | 19120.104 ft·lb/(min·ft²) |
| 5 W/in² | 31866.84 ft·lb/(min·ft²) |
| 10 W/in² | 63733.68 ft·lb/(min·ft²) |
| 20 W/in² | 127467.36 ft·lb/(min·ft²) |
| 50 W/in² | 318668.4 ft·lb/(min·ft²) |
| 100 W/in² | 637336.8 ft·lb/(min·ft²) |
| 1000 W/in² | 6373368 ft·lb/(min·ft²) |
Watt per Square Inch (W/in²)
Definition: A US customary heat flux unit sized to inch-scale component and process areas.
History: A natural combination of the watt with the US customary square inch, used in American industrial heating-element and electronics design.
Current use: Common on US industrial heating-element (cartridge heater, strip heater) datasheets, which rate maximum safe watt density per square inch of heating surface.
Foot Pound per Minute per Square Foot (ft·lb/(min·ft²))
Definition: A mechanical-work-based US customary heat flux unit — foot-pounds of work-equivalent energy passing through one square foot per minute.
History: Rooted in the US customary mechanical work tradition (foot-pound, the same unit used for torque and mechanical energy), applied here to a heat-transfer-rate context.
Current use: Rare in modern practice, occasionally found in older US mechanical engineering references that expressed heat flow in mechanical work units rather than thermal Btu units.
Supported Units
| Unit | Symbol | In W/m² |
|---|---|---|
| Watt per Square Meter | W/m² | 1 W/m² |
| Kilowatt per Square Meter | kW/m² | 1000 W/m² |
| Watt per Square Centimeter | W/cm² | 10000 W/m² |
| Watt per Square Inch | W/in² | 1550.0031 W/m² |
| Kilocalorie (IT) per Hour per Square Meter | kcal/(h·m²) | 1.163 W/m² |
| Calorie (IT) per Second per Square Centimeter | cal/(s·cm²) | 41868 W/m² |
| Btu (IT) per Hour per Square Foot | Btu/(h·ft²) | 3.1546 W/m² |
| Btu (IT) per Second per Square Foot | Btu/(s·ft²) | 11356.53 W/m² |
| Horsepower per Square Foot | hp/ft² | 8026.65 W/m² |
| Foot Pound per Minute per Square Foot | ft·lb/(min·ft²) | 0.2432 W/m² |
About These Parameters
- Value
- The heat flux density value you want to convert, expressed in the "From" unit. Accepts decimals.
- From Unit
- The unit your input value is currently measured in — a solar spec sheet's W/m², or a US HVAC load calculation's Btu/(h·ft²).
- To Unit
- The unit you want the result converted into. Use the swap button to flip From and To instantly.
How Heat Flux Density Conversion Works
The Formula
Every unit here is defined by a fixed multiplier relative to watts per square meter. To convert a value from one unit to another:
result = value × (factor of "From" unit ÷ factor of "To" unit)
For Watt per Square Inch → Foot Pound per Minute per Square Foot: multiply by 6373.368. For example, 1 W/in² × 6373.368 = 6373.368 ft·lb/(min·ft²).
Solar Irradiance
"1,000 W/m²" is the standard reference solar irradiance used to rate solar panels under laboratory "Standard Test Conditions" — roughly what a clear, midday sun delivers to a surface facing directly toward it. Real-world irradiance varies constantly with time of day, cloud cover, and season, which is why a panel's rated wattage (measured at that fixed 1,000 W/m² reference) rarely matches its actual output at any given moment.
Heat Flux Density vs. Heat Density
This page's units are all RATES (power per area, e.g. watts per square meter) — how fast energy is moving right now. The site's separate Heat Density Converter covers the cumulative TOTAL (energy per area, e.g. joules per square meter) — how much energy has landed altogether over some period. Multiplying a heat flux density by a duration of time gives you a heat density, the same relationship speed has to distance.
Example
A heat flux density of 1 W/in² equals 6373.368 ft·lb/(min·ft²). For scale, peak midday solar irradiance is around 1,000 W/m² (about 317 Btu/(h·ft²)), while a typical well-insulated wall might lose heat at only a few W/m² on a cold day.
Frequently Asked Questions
How many Foot Pounds per Minute per Square Foot are in 1 Watt per Square Inch?
1 Watt per Square Inch (W/in²) equals exactly 6373.368 Foot Pounds per Minute per Square Foot (ft·lb/(min·ft²)).
Why does this page have so many units compared to other converters?
Heat flux density is used across an unusually wide range of fields — solar engineering, HVAC, laser physics, industrial heating, and classical thermodynamics — each of which historically settled on its own preferred combination of energy, time, and area units, so this page collects the most commonly seen ones from each.
What's a normal heat flux density value for solar panels?
Solar panels are rated at a standard 1,000 W/m² reference irradiance, but real-world sunlight typically ranges from near 0 (night, heavy cloud) up to around 1,000-1,100 W/m² at clear-sky, high-sun conditions, varying with latitude, season, and time of day.
How accurate are these conversions?
Every conversion factor used here is the exact, internationally recognized relationship between the underlying power, energy, and area units — results are limited only by floating-point display precision, not by rounded conversion constants.