Duct Size Worksheet
A duct size worksheet turns airflow into a round or rectangular duct size, then checks velocity and straight-duct pressure loss before fittings are added.
duct size worksheet duct size calculator by cfm equivalent round duct worksheet
Velocity sizing
A = Q / v
Worksheet rows
- Airflow: use design airflow through the specific trunk or branch.
- Target velocity: sets first-pass free area and round diameter.
- Friction rate: screens the pressure drop for straight duct.
Follow-up
After picking the duct size, run duct friction loss for equivalent length and then total external static pressure for blower margin.
Related pages
- Duct size calculator - round and rectangular duct sizing from airflow.
- Duct friction loss calculator - run-level pressure loss from duct size and length.
- HVAC static pressure calculator - total external static pressure and blower margin.
- Grille size calculator - face velocity and free-area checks for terminals.