Efficiently calculate duct velocity and velocity pressure for your HVAC systems. Our online tool helps engineers, technicians, and DIY enthusiasts optimize airflow, reduce friction losses, and ensure optimal system performance for both residential and commercial applications. Get accurate results for rectangular or circular ducts quickly and easily to enhance energy efficiency and occupant comfort.
Formula:
Use the following formulas to determine duct velocity and velocity pressure:
- Duct Velocity (V) = Airflow (Q) / Duct Cross-sectional Area (A)
- Velocity Pressure (Pv) = (V / 4005)²
Where:
- Q: Airflow Volume in Cubic Feet per Minute (CFM)
- A: Duct Cross-sectional Area in square feet (ft²)
- For Rectangular Ducts: A = (Width (in) * Height (in)) / 144
- For Circular Ducts: A = π * (Diameter (in) / 2)² / 144
- V: Duct Velocity in Feet Per Minute (FPM)
- Pv: Velocity Pressure in inches water gauge ("w.g.)
- 4005 is a constant for standard air at 70°F and 29.92 in. Hg.