Pipe Pressure Drop Calculator
What is the friction pressure drop through this pipe?
Single calculationv1.1.0Verified 2026-11-01Runs in your browser
Spec sheet
darcy_weisbach_colebrook · v1.1.0Method
Darcy–Weisbach; Colebrook solved exactly by Clamond's algorithm (fluids)
- 01
v = Q / (π D² / 4) - 02
Re = ρ v D / μ - 03
Laminar (Re < 2040): f = 64 / Re - 04
Turbulent: 1/√f = −2 log₁₀(ε/3.7D + 2.51/(Re√f)) — Clamond (2009) - 05
ΔP = f · (L/D) · ρ v² / 2
Limits — read before relying on it
- Straight pipe only; add fittings and valves separately (K-values or equivalent length).
- Incompressible, single-phase, Newtonian fluid.
- Transitional flow (2040 ≤ Re < 4000) is uncertain; the result is reported with a warning.
Sources
- Colebrook (1939), Turbulent flow in pipes, J. ICE 11, 133–156standard
- Clamond (2009), Efficient resolution of the Colebrook equation, Ind. Eng. Chem. Res. 48, 3665–71standard
- fluids (MIT) — friction factors and roughness table, ported to TypeScript ↗library