Convert Feet per Minute to CFM per Square Foot

Formula

ft³/(ft²·min) = ft/min × 1

Derivation from SI units:

• 1 ft/min = 0.3048 m ÷ 60 s = 0.00508 m/s
• 1 ft³/(ft²·min) = 0.3048³ m³ ÷ (0.3048² m² × 60 s) = 0.00508 m/s = 1 ft/min
• 1 ft/min = 0.00508 m/s ÷ 0.00508 m/s per ft³/(ft²·min) = 1 ft³/(ft²·min)

Both units are defined exactly, so the factor is exact. Foot per Minute definition: foot per minute; CFM per Square Foot definition: cubic foot per square foot per minute.

Worked examples

1. A filter face velocity of 300 ft/min is the same as 300 ft³/(ft²·min) of face area.
   300 ft/min × 1 = 300 ft³/(ft²·min)
2. A baghouse running at 5 ft/min has an air-to-cloth ratio of 5 ft³/(ft²·min).
   5 ft/min × 1 = 5 ft³/(ft²·min)

Where it's used

These are the same unit: one CFM per square foot of area is a velocity of one foot per minute. The factor is exactly 1.

Foot per Minute to other face velocity & air permeability units

Frequently asked questions

Sources

• Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "foot per minute (ft/min)".
• ASTM D737 Standard Test Method for Air Permeability of Textile Fabrics, ASTM International , inch-pound results in ft³/min/ft².
• Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "foot per minute".

Last reviewed: 2026-10-15. Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.