Pipe head loss calculator
Calculate multi-segment head loss with Darcy–Weisbach and Colebrook, compare scenarios, optimize diameters, and export CSV results with integrated charts.
Pipe head loss calculator (Darcy–Weisbach + Colebrook)
Calculate multi-segment head loss, compare scenarios, and optimize the minimum diameter with charts and CSV export.
Input data
Basic
Advanced
Segments
| Label | L | Inner D | Material | ε (mm) | K | Δz (m) | Actions |
|---|
Results
| Segment | Accum. distance | v (m/s) | Re | f | hf (m) | hm (m) | Δz (m) | H segment | H accum. | ΔP segment | ΔP accum. |
|---|
Cumulative H vs distance
f vs Re (simplified chart)
Approximate curve for the scenario's relative roughness.
Compare scenarios
Set up to 3 scenarios and compare total H, ΔP, and power. Use “Clone A → B/C” to copy the segments.
| Scenario | Total H (m) | Total ΔP | Hydraulic power | Shaft power | Critical segment |
|---|
Cumulative H vs distance (comparison)
Optimize minimum diameter
Segments (no D)
| Label | L (m) | ε (mm) | K | Δz (m) | Actions |
|---|
Result
| Diameter (mm) | Total H (m) | Max v (m/s) | Status |
|---|
Auditable step by step
Review the calculation per segment, with area, velocity, Reynolds, and partial losses.
What is the difference between Darcy–Weisbach and Hazen–Williams?
Darcy–Weisbach applies to any fluid and flow regime, while Hazen–Williams is empirical for water and specific conditions. This calculator uses Darcy–Weisbach and Colebrook for broader applicability.
What is the friction factor f?
It is a dimensionless coefficient that relates friction losses to velocity and pipe roughness. It is computed with Colebrook in turbulent flow and with 64/Re in laminar flow.
How do diameter and roughness affect losses?
A larger diameter reduces velocity and head loss. Relative roughness ε/D increases f and losses, especially in turbulent flow.
What does the K coefficient represent?
It is the aggregated minor loss of the segment (valves, elbows, inlets, outlets). It is used in hm = K·(v²/2g).
How should I interpret H and ΔP?
H is the head loss in meters of fluid column. ΔP is the equivalent pressure drop, calculated as ρ·g·H.
What happens in the transitional regime (Re 2000–4000)?
Friction is uncertain and depends on disturbances. The calculator shows a non-blocking warning so you can review the design.
How is the elevation difference Δz included?
Δz adds or subtracts energy in the segment (positive is uphill). It is included directly in the segment H along with friction and minor losses.
Does it have regulatory limitations?
The result is a reference hydraulic calculation. For regulated projects, compare with local codes and consider safety factors.
