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Volumetric Flux

gfdtogpm/ft²

Convert US gallons per square foot per day (gfd) to US gallons per minute per square foot (gpm/ft²).

Factor1 gfd = 0.0006944444 gpm/ft²

Converter

gfd

Accepts numbers or expressions, e.g. 150 + 14.7

Result
1gpm/ft²

Rendered to 6 significant figures.

Formula

Formula
gpm/ft² = gfd × 0.0006944444

Multiply any value in US gallons per square foot per day by 0.0006944444 to obtain the value in US gallons per minute per square foot.

Worked example

Convert 1440 gfd to gpm/ft².

  1. 01Start with 1440 gfd.
  2. 02Multiply by the conversion factor: 1440 × 0.0006944444 = 1 gpm/ft².
Result1440 gfd = 1 gpm/ft²

Conversion table

gfdgpm/ft²
10.00069444
20.0013889
50.0034722
100.0069444
200.013889
500.034722
1000.069444
2000.13889
5000.34722
10000.69444

Reference values rounded to 5 significant figures for display.

FAQ

What is the conversion factor from gfd to gpm/ft²?
1 gfd equals 0.0006944444 gpm/ft². To convert, multiply the value in US gallons per square foot per day by 0.0006944444.
How do I convert 1 gfd to gpm/ft²?
1 gfd = 0.000694444 gpm/ft². For any value, multiply by 0.0006944444.
How do I convert gpm/ft² back to gfd?
Divide by the same factor — or equivalently, multiply by 1440. So 1 gpm/ft² = 1440 gfd.
When would I need to convert US gallon per square foot per day to US gallon per minute per square foot?
Volumetric-flux conversions between gfd and gpm/ft² are routine in membrane filtration (RO, UF, MF, NF permeate flux), hydraulic loading specification, water-treatment design, hydrometallurgy and packed-bed column loading, and environmental engineering. LMH (L/m²/h) and gfd (gal/ft²/day) dominate membrane datasheets; m³/m²/h and m³/m²/day cover SI engineering ladders; m/day and cm/s appear as superficial velocity in hydromet and packed-bed work. Volumetric flux is the same physical quantity as superficial velocity (m³/m²/s ≡ m/s) but is kept distinct from the velocity and flow categories because the engineering intent is volumetric throughput per unit area, not bulk motion or total throughput.
Is the conversion exact?
The factor shown is precise to at least 7 significant figures. For most process-engineering work this is far better than instrument accuracy. For metrology or trade applications, refer to the relevant national standard (NIST, BIPM, ISO 80000).

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