Pump Flow Calculator
Enter pipe internal diameter and design velocity to estimate theoretical pipe flow locally.
A QUICK WALKTHROUGH
How to use this tool
- Enter the measured internal diameter in millimetres.
- Enter a design velocity in metres per second.
- Review theoretical flow in L/s and m³/h.
Formula
Flow = π × (internal diameter ÷ 2)² × velocity. Diameter is converted from millimetres to metres before calculation.
Scope
This estimates pipe flow only. It does not predict pump performance, pressure, friction loss, head, or a suitable pump. Use verified system requirements and manufacturer data.
GOOD TO KNOW
Common questions
Does this select a pump?
No. It estimates theoretical flow through a circular pipe using your inputs.
Are velocity recommendations built in?
No. You provide the velocity.