Irrigation in the Pacific Northwest

Pipe Water Velocity and Minimum Pipe Diameter

Use the water velocity form to calculate the velocity of water in a pipe. Use the second form to calculate the diameter of a pipe required for 5 fps pipe velocity.

Learn more about the units used on this page.

Water Velocity

Flow Rate:
Pipe Inside Diameter:
Water Velocity:


Minimum Pipe Diameter (5 fps)

Flow Rate:
Minimum Pipe Diameter:



The Equation

This calculator uses this formula to determine the water velocity inside of a pipe.


WSU Prosser - IAREC, 24106 N Bunn Rd, Prosser WA 99350-8694, 509-786-2226,