Duct Sizer Calculator
Calculate optimal duct sizes using Equal Friction or Equal Velocity methods. Supports round and rectangular ducts with pressure drop analysis based on McQuay methodology.
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Calculator Inputs
Cubic Feet per Minute (CFM)
Enter duct run length to calculate total pressure drop
Round Duct
14"
Rectangular Equivalent
18" × 9"
Actual Velocity
935 FPM
Round Duct
Exact Diameter13.9in
Recommended Size14in
Duct Area1.069sq.ft
Rectangular Sizer
Enter duct width to calculate required height for equal friction performance
Dimensions
25 × 0 in
Equivalent Diameter
13.7 in
Aspect Ratio (W:H)
1:2.00
Pressure Drop
Actual Velocity935FPM
Friction Loss0.0965in.wg/100ft
Velocity Pressure0.0546in.wg
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DISCLAIMER
This calculator provides ESTIMATES for preliminary planning purposes. Results are based on standard assumptions and may not reflect your specific project conditions.
By using this tool, you acknowledge that:
1. All calculations are approximate and based on typical industry standards and assumptions.