Feb 19, 2024 · Identify the volume of air (in CFM) that will be passing through the duct. Choose the appropriate duct size from the table based on the identified volume of air.

TEL is the Total Effective Length of the longest supply run and the longest return run.

Jun 3, 2025 · Do your own calculations and compare them to our chart – or use the chart for quick, accurate calculations for duct size based on CFM needed for a room. One size is given …

This article introduces a user-friendly Duct CFM Calculator that allows you to calculate airflow based on duct shape, size, and air velocity. Designed to support both round and rectangular …

Enter an internal duct size in inches (this must be limited to a maximum aspect ratio of 5:1 for the results to be valid) The resulting velocity and pressure drop per unit length are displayed in the …

Jul 27, 2025 · Use our handy duct sizing chart as a quick reference team for help with layout. Air that moves too fast whistles, vibrates ducts, or blasts out grilles.

This downloadable provides quick access to standard duct dimensions for rectangular and round ducts — including airflow values, velocity ranges, and aspect ratios.

Step One - Identify the volume of air that will be passing through the duct Step Two - Select the duct size from the table that can carry that volume of air Step Three - If desired airflow …

Easily calculate duct size or airflow (CFM) for HVAC systems. Get accurate results instantly with our Duct Size & CFM Calculator.

Oct 7, 2025 · Learn to calculate duct sizes, read charts, and apply industry standards for optimal HVAC airflow. Proper duct sizing is the foundation of efficient HVAC systems, yet many …