Duct Sizer

HVAC air duct sizing · equal friction & velocity methods
Inputs
Sizing Method
Results
Round Duct
— in. dia.
Velocity
—
Friction
—
Adjust Size
in. dia.
Rectangular Duct — Equal Friction Equivalent
— × — in.
Velocity
—
Friction
—
Aspect Ratio
—
Adjust Size
in.
⚠ Aspect ratio exceeds 4:1 — not recommended (SMACNA).
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This calculator handles one step. AIM Works runs the complete MEP design workflow — thermal load calculations, duct & pipe networks, equipment selection, code compliance, and an AI design assistant — in one tool.

  • ✓  ASHRAE 62.1 ventilation + CLTD/CLF/RTS load methods
  • ✓  Darcy-Weisbach pipe & duct network solvers
  • ✓  ASHRAE 90.1 / IMC / NFPA compliance checks
  • ✓  20 free AI design messages included in trial
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