Calculate pressure loss along a pipe using the Darcy-Weisbach equation.
Head loss rises with the square of velocity and inversely with diameter, so oversizing a pipe reduces pumping cost sharply. Converting head to pressure multiplies by density and gravity. Since loss scales with v², halving velocity by doubling pipe area cuts friction loss to about a quarter — the main lever on lifetime pumping energy.
Head Loss
h_f = f (L ÷ D) (v² ÷ 2g)
h_f = f (L ÷ D) (v² ÷ 2g) Head loss rises with the square of velocity and inversely with diameter, so oversizing a pipe reduces pumping cost sharply. Converting head to pressure multiplies by density and gravity.
Since loss scales with v², halving velocity by doubling pipe area cuts friction loss to about a quarter — the main lever on lifetime pumping energy.
This calculator takes 5 inputs: Pipe length, Pipe internal diameter, Flow velocity, Darcy friction factor, Fluid density. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.