Pipe Sizing Calculator
The Pipe Sizing Calculator picks the smallest standard pipe that keeps velocity in the safe economical range for a given flow. Example: for 300 L/min of water through 50 m of PVC pipe, Recommended nominal size = 50 mm, Velocity = 2.31 m/s, Flow = 18 m³/h (per ASHRAE 2021 Ch.22 | PSME Code | PNS ISO 4427).
How it works
Computed from your inputs per ASHRAE 2021 Ch.22 | PSME Code | PNS ISO 4427.
Worked example (Plumbing & Pumps)
Inputs: 300 L/min of water through 50 m of PVC pipe.
| Result | Value |
|---|---|
| Recommended nominal size | 50 mm |
| Velocity | 2.31 m/s |
| Flow | 18 m³/h |
Computed live by WorkHive's calculation engine; standard: ASHRAE 2021 Ch.22 | PSME Code | PNS ISO 4427.
How to use this calculator
- Enter the figures for the duty you are sizing: the worked example below uses 300 L/min of water through 50 m of PVC pipe.
- The calculator returns Recommended nominal size, Velocity, Flow, computed per ASHRAE 2021 Fundamentals Ch.22 | PSME Code | PNS/ISO 4427.
- Check the worked example to confirm the method matches how you would do it by hand, then run your own numbers in the interactive tool.
FAQ
What is a water pipe size calculator by flow rate?
The Pipe Sizing Calculator is a free online tool that computes picks the smallest standard pipe that keeps velocity in the safe economical range for a given flow. It shows the formula and a fully worked example so you can check the method, not just the number.
How is it calculated?
The result is computed from your inputs following ASHRAE 2021 Fundamentals Ch.22 | PSME Code | PNS/ISO 4427. The worked example on this page shows a real computation with real numbers.
Is the calculator free?
Yes. WorkHive's engineering calculators are free to use, no sign-up needed for the tools. WorkHive is a free, offline-first maintenance platform built for Philippine industrial plants.
Run it on your own numbers
Open the interactive Pipe Sizing Calculator in WorkHive: free, no sign-up needed for the calculators.