The Maximum Internal Diameter of the pipe can be calculated when the following values are known:

  • Pipe internal roughness
  • Pipe length
  • Pipe elevation change
  • Fittings
  • Required flow rate
  • Maximum allowed pressure drop


The Pipe Diameter can be calculated for both Liquids and Gases.  For information about selecting a fluid, see: Fluids Database

For more information about working with gases, see: Working with Compressible Fluids


For more information about the theory and formulas used to calculate the flow rate, see: Calculation Theory and Method of Solutions