0
TipEnter a value. Length tools treat a bare number as inches.
Fan Law 1
Fan Law 2
Fan Law 3
Seg Radius
Ir/Pitch
x³
³√x
Arc
Riser
Ir/Jack
ArcSine
ArcCos
ArcTan
Offset
Column/Cone
mm
x10ʸ
A new
B new
LawCos
1/x
Swap M+
A
B
C
Clear All
M−
M1
M2
M3
+/−
ArcK
VP ↔ FPM
dms ↔ deg
Prefs
%
Equal friction method
Duct calculator
0/2
Enter any two values. The other two solve automatically.
Enter any two values. The other two solve automatically.Round duct flow diagram. Air flow, Q: no value, expected. Velocity, V: no value, expected. Round diameter, ØD: no value, expected. Friction loss, ΔP: no value, expected. Equivalent rectangular size will appear after the round duct is solved. A candidate must carry the same airflow with friction within ±10%.
Equivalent at the same airflow
Equivalent rectangular ducts
Solve a round duct to see standard rectangular options.
Straight average sheet-metal duct · standard air · internal dimensions. Add fitting and equipment losses separately.