Pipe & Duct Sizing Calculator
Size pipes and ducts using the Darcy-Weisbach equation. Calculate pressure drop, fitting losses, Reynolds number, and velocity for hydronic and air distribution systems.
ASHRAE · SMACNA · CIBSE Guide C
Flow Configuration
Material
Roughness
0.0015 mm
Max Temp
200 °C
Max Press.
1200 kPa
Fittings
No fittings added
Pressure Drop Breakdown
Total: 88.16 kPa
Recommended Size
NPS 1-1/4
DN32 · ID 35.1 mm
Velocity
2.07m/s
Reynolds
72k
Friction Factor
0.01935
Total Pressure Drop
88.16kPa
Velocity
Within limits
Flow Regime
Turbulent
Alternative Sizes
| Size | Velocity | dP (kPa) | Status |
|---|---|---|---|
| NPS 1 (DN25) | 3.60 m/s | 352.70 | Too Small |
| NPS 1-1/4 (DN32) | 2.07 m/s | 88.16 | Selected |
| NPS 1-1/2 (DN40) | 1.52 m/s | 41.04 | Oversized |