Pipe Sizing Calculator
Estimate a suitable pipe size from flow rate, target velocity, pipe material and optional pressure-drop limits.
Choose your units and design conditions. Results update automatically as you change inputs.
Recommended Pipe Size
Pressure-drop compliance is only assessed when a maximum is entered.
How to Use the Calculator
- Enter the design flow rate and select the matching flow unit.
- Choose the pipe material / standard and service type.
- Set a target velocity, velocity warning limit, and optional pressure-drop limit.
- Enter water temperature and a round-up margin if needed. Results update automatically.
- Review the recommended size and verify the final selection against project specifications and local codes.
Assumptions and Limitations
The theoretical inside diameter is calculated from Q = A × v. Pressure drop is estimated with Darcy–Weisbach and a friction factor based on Reynolds number and approximate material roughness. Listed dimensions are representative sizing data for the options shown, not a substitute for the manufacturer's current product tables. Copper wall thickness can vary by product; the MDPE option uses an SDR 11 approximation. Fittings, valves, elevation, transient effects, glycol mixtures, and system-specific design requirements are not included. If no listed size meets the selected constraints, the calculator reports that no suitable listed size was found instead of claiming compliance.
