DuctSizer
iOS
Size a duct in seconds, from the ladder.
DuctSizer turns airflow into duct sizes instantly: enter CFM or L/s with a friction rate or velocity target and read every valid size at a glance — round diameter plus rectangular options for the joist depth you actually have. Friction, velocity, and limit warnings come with each result, in imperial or SI. Pro adds reverse sizing, fittings and total effective length, altitude and temperature correction, and saved jobs.