Pipe Head-Loss Calculator (Darcy–Weisbach + fittings)

Pipe Length (m):

Pipe Diameter (mm):

Pipe Material:

Flow Rate (m³/h):

Fluid Viscosity (cP):

Fittings (counts)

Short-radius 90° elbows:

Long-radius 90° elbows:

45° bends:

Tees (flow through run):

Tees (branch flow):

Concentric reducers:

Ball valves (full open):

Globe valves (full open):

Major Loss: m

Minor Loss: m

Total Loss: m

About

This calculator computes major head loss using Darcy–Weisbach and sums minor losses from a variety of fittings. K-values used are engineering typical estimates; adjust counts to reflect your piping.

Typical K-values used:

Short-radius 90° elbow: K = 0.30
Long-radius 90° elbow: K = 0.20
45° bend: K = 0.20
Tee (flow through run): K = 0.60
Tee (branch flow): K = 1.50
Concentric reducer: K = 0.50
Ball valve (full open): K = 0.05
Globe valve (full open): K = 10.0

These are approximations; consult manufacturer data or fluid mechanics references for precise values.

FAQs

Q: Can I change K-values?
A: Not in this version — tell me which values you prefer and I can add inputs.

Q: What density is assumed?
A: Water at 1000 kg/m³. I can add density input if you like.

Q: Are fittings sensitive to Reynolds number?
A: K-values are somewhat dependent on flow regime; listed values are typical for turbulent flows.