Flow Rate Calculator
Find volumetric flow through a full circular pipe using mean velocity.
Formula
Q = Av = πd²v/4
Internal diameter: 100 mm · Mean velocity: 2 m/s · Flow (m³/s) ≈ pi×(100 mm × 0.001 m/mm)^2×(2 m/s)÷4 · Flow (L/min) ≈ (0.01570796327)×60000
How to use
- Enter the pipe’s internal diameter.
- Enter the cross-sectional mean velocity.
- Read flow in m³/s and L/min.
Examples
- A 100 mm bore at 2 m/s carries about 942.478 L/min.
Frequently asked questions
Which diameter is used?
The actual internal diameter, not nominal pipe size.
Can I enter centerline velocity?
Use mean velocity across the section; centerline velocity may differ.
Does it predict flow from pressure?
No. It does not model friction, pumps or partially filled pipes.
Sources
Updated: