Flow Rate Calculator

Flow Rate Calculator

How much flow rate will travel through the pipe? A simple calculator will help you estimate the flow rate in your pipe based on the inner diameter of the pipe and fluid velocity.

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Also see
Velocity*, m/s
Pipe Inner Diameter*, mm





Why use our calculator?

When organizing the water supply system in the house, sooner or later you will come across the term "volumetric water flow rate". This parameter defines volume of water that passes through a given cross-sectional area per unit time. Knowing this value is needed when choosing the diameter of a pipe, garden hose, shower head, or faucet.

This calculator allows you to estimate the flow rate of water in the pipeline based on the known inner diameter of the cross section of the pipe and the average water velocity. The basic formula for calculation: Q = π × (d2 / 4) × V, where d – inner diameter of the pipe, V – water velocity. The optimum water velocity in the pipe is from 0.6 m/s to 1.5 m/s (2-5 ft/s), the maximum is 3 m/s (10 ft/s). Note that you must enter the INNER diameter of the pipe, not the OUTSIDE.

How do I estimate the Flow Rate?

  1. Enter the velocity value.
  2. Enter the inner diameter of the pipe.
  3. Click the "Calculate" button.
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