Calculate pipe head loss easily. Compare methods, inspect flow behavior, and export results. Built for practical engineering estimates and quick design reviews.
Use the buttons below to export calculation rows.
| Method | Length (m) | Diameter (mm) | Flow (m³/h) | Velocity (m/s) | Total Head Loss (m) | Pressure Drop (kPa) |
|---|---|---|---|---|---|---|
| Darcy-Weisbach | 100.00 | 150.00 | 40.00 | 0.6288 | 0.9662 | 9.4562 |
The graph shows how total head loss changes with flow rate.
| Scenario | Length (m) | Diameter (mm) | Flow (m³/h) | Method | Total K | Estimated Head Loss (m) |
|---|---|---|---|---|---|---|
| Cooling Water Loop | 80 | 100 | 25 | Darcy-Weisbach | 1.8 | 2.41 |
| Irrigation Main | 150 | 200 | 60 | Hazen-Williams | 2.2 | 3.76 |
| Process Transfer Line | 120 | 150 | 40 | Darcy-Weisbach | 2.5 | 1.14 |
| Building Service Pipe | 60 | 75 | 12 | Hazen-Williams | 3.0 | 3.98 |
Velocity: V = Q / A
Pipe Area: A = πD² / 4
Reynolds Number: Re = ρVD / μ
Darcy-Weisbach Friction Head: hf = f(L/D)(V² / 2g)
Minor Loss Head: hm = K(V² / 2g)
Total Head Loss: htotal = hf + hm
Pressure Drop: ΔP = ρgh
Swamee-Jain Friction Factor: f = 0.25 / [log10((ε / 3.7D) + (5.74 / Re0.9))]²
Hazen-Williams Head Loss: hf = 10.67LQ1.852 / (C1.852D4.8704)
Darcy-Weisbach works broadly across fluids and flow conditions. Hazen-Williams is common for water systems and practical piping estimates.
This calculator estimates head loss caused by straight pipe friction and minor losses from bends, valves, entrances, and exits. It helps compare system resistance across operating conditions, supports pump sizing checks, and provides a practical way to inspect sensitivity to changing flow rate.
For turbulent flow, the Darcy option uses the Swamee-Jain approximation to estimate friction factor quickly. For water distribution style checks, the Hazen-Williams option provides a familiar empirical alternative. Always verify units before relying on design outputs.
Use conservative assumptions when system reliability matters. If your fluid is non-Newtonian, compressible, multiphase, or temperature dependent, use a more detailed model before final design approval.
Head loss is the energy lost as fluid moves through pipe length and fittings. It appears as reduced pressure or elevation head and affects pump requirements.
Use Darcy-Weisbach when you need a physics-based method that handles many fluids, pipe materials, and flow regimes more consistently than empirical water-only methods.
Hazen-Williams is commonly used for water flow in civil and building systems. It is simple and practical, but less general than Darcy-Weisbach.
Smaller diameters increase velocity for the same flow rate. Higher velocity increases friction and minor losses, so head loss rises quickly as diameter falls.
Minor losses come from valves, elbows, tees, entries, exits, reducers, and similar components. Their effect is usually combined using a total K value.
Reynolds number helps identify whether flow is laminar or turbulent. That matters because friction factor behavior changes significantly between regimes.
Yes, it is useful for preliminary pump sizing and system checks. Add elevation change and equipment losses for a more complete total dynamic head estimate.
The CSV file is easy to edit in spreadsheet software. The PDF file is mainly for sharing, printing, and record keeping.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.