Duct CFM @ .08 supply .05 return

This calculator does not replace good ACCA manual D or SMACNA principles. It does however provide basic duct sizes and CFMs based on these principles. This calculator can be used to estimate CFM or duct size using round Metal or Flexible "properly installed" typical duct runs. Extended runs, multiple turns, poor installation can all affect resulting airflow.

Enter at least 2 values, then click Calculate.