Free Flow Rate Calculator

Calculate volumetric and mass flow rate from pipe diameter and flow velocity.

mm
m/s
kg/m^3

Volumetric Flow Rate

0.01571 m^3/s

Flow Rate (litres/s)15.71 L/s
Mass Flow Rate15.708 kg/s

Volumetric Flow Rate vs Pipe Inner Diameter

Volumetric & Mass Flow Rate

Flow rate through a pipe depends on the cross-sectional area and the average fluid velocity.

Formulas

Q = A V = (pi D^2 / 4) V (volumetric flow)

m_dot = rho Q = rho A V (mass flow)

where D is the pipe diameter, V is the average velocity, and rho is the fluid density.

Example Calculation

Water flowing at 2 m/s through a 100 mm diameter pipe.

  1. 01D = 100 mm = 0.1 m
  2. 02A = pi x 0.1^2 / 4 = 0.007854 m^2
  3. 03Q = 0.007854 x 2 = 0.01571 m^3/s = 15.71 L/s
  4. 04Mass flow = 1000 x 0.01571 = 15.71 kg/s

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