How does the Duct Sizing Calculator work?

Use friction loss tables or duct calculators Then: Recommended velocity: main ducts 4-6 m/s, branches 3-4 m/s Then: Size ducts for <25 Pa/100m static pressure drop.

Can you give an example of how to use the Duct Sizing Calculator?

Example: Input CFM 2500, round duct, 0.15 mmWG friction gives a result of Diameter ≈ 500 mm for low-loss duct design (Provides good velocity).

Is the Duct Sizing Calculator free to use?

Yes — completely free with no registration, download, or subscription required. All calculations happen instantly in your browser.

How accurate is the Duct Sizing Calculator?

Our Duct Sizing Calculator uses verified mathematical formulas and is accurate to multiple decimal places. Results are calculated in real-time using the same methods used by professionals.

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Duct Sizing Calculator

Airflow (CFM)

Velocity (ft/min)

Duct sizing balances airflow velocity, pressure drop, and cost. Proper sizing ensures system performance and efficiency.

Difficulty:intermediate

References

›Duct Sizing — Wikipedia

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Duct Sizing Calculator

Duct Sizing Calculator

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