Pipe Flow Calculator

Calculate the volumetric flow rate of water based on pipe diameter and velocity.

Flow Rate (GPM) 48.9
Liters / Minute 185.1

How Plumbing Flow Works

The amount of water a pipe can carry depends entirely on two factors: the cross-sectional area of the pipe (diameter) and how fast the water is moving (velocity).

The Formula: Q = A × v (Flow Rate = Area × Velocity)

Pro Tip: In standard residential and commercial plumbing, engineers aim to keep water velocity between 2 and 5 feet per second. Speeds higher than 5 fps can cause pipe erosion, loud noises, and "water hammer" (a banging sound when valves close quickly).