HVAC Duct Sizing Calculator
Size ducts for proper airflow and velocity.
Airflow Requirements
Total Cubic Feet per Minute needed for the room/zone.
Design friction rate (Inches Water Column per 100ft).
Recommended Duct Size
Round Duct
Exact: 0.0"
Square Equivalent
Approximate square duct
Performance Check
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HVAC Duct Sizing Calculator for HVAC contractors
HVAC Duct Sizing Calculator helps HVAC contractors size ducts quickly during estimating. Enter CFM and velocity targets and get duct size recommendations you can use immediately in your bid or project file.
Used by contractors across California, Texas, Florida, New York, and Illinois, with active users in Los Angeles, Houston, Dallas, Chicago, Phoenix, Atlanta, Seattle, and Denver.
Quick answer: what does this tool do?
Calculate duct sizes based on airflow and velocity.
How should I apply the results?
Use sizes for takeoffs and equipment coordination.
Is this suitable for public bids?
Yes. The inputs align with typical DOT, municipal, and federal bid requirements.
What keywords does this tool target?
HVAC duct size calculator, duct CFM calculator
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