Conduit calculations (pressure losses, velocity)

Pressure losses in the conduit

Pressure losses in the conduit

These calculations can help you to estimate the pressure losses, and flow velocity in the conduit (hose, pipe or tube) and check/correct conduit ID.

Calculations Notes:

  • The recommended flow velocity in conduits you can find at the article Recommended flow velocity.
  • The assumption: pressure losses on elbows, fittings at calculated conduit is zero.
  • Height difference between IN and OUT points needs to calculate hydrostatic pressure what will be added to pressure losses, if IN point is below OUT (use positive value), or subtracted from pressure losses, if IN point is upper than OUT (use negative value). Use value “0” if height difference can be neglected.
  • To find Darcy friction factor there are different formulas used:



Operation data
Select hydraulic oil:
Oil Viscosity cSt
Oil Density
Flow in the conduit
Conduit Parameters
Type of conduit line:
Conduit material roughness:
See full table of roughness values

Conduit ID size
Conduit lenght L=L1+H
Height difference “H” between IN and OUT points



Click “Calculate” button to show the results



“Hydraulic losses in pipes” by Henryk Kudela
“Pressure drop evaluation along pipelines” by PetroWiki
“Pressure loss in pipe” by Neutrium
“Absolute roughness of pipe material” by Neutrium
“A Review of Explicit Approximations of
Colebrook’s Equation” by University of Belgrade Faculty of Mechanical Engineering

“Darcy friction factor formulae” by Wikipedia
“Darcy Friction Factor Formulae in Turbulent Pipe Flow” by Jukka Kiijarvi
“Pipe flow with friction losses – solutions using HP and TI calculators” by Gilberto E. Urroz
“Pipe Flow: A Practical and Comprehensive Guide” by Donald C. Rennels and Hobart M. Hudson

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