Pipe run · calculator
Water Pipe Size Calculator
Estimate the required hydraulic inside diameter for a target flow, pressure loss, length, and roughness coefficient.
Method shownUnits declaredLimits included
Input bench
Enter operating conditions
Estimate required pipe inside diameter.
Interactive inputs load immediately when JavaScript is available.
Applicability
Use the model within its limits
Select a real pipe whose verified inside diameter meets the result, then check velocity, fittings, and elevation.
Method record
What this result represents
- System
- Pipe run
- Formula
- d = [4.52LQ¹·⁸⁵ ÷ (hC¹·⁸⁵)]¹/⁴·⁸⁷
- Review
- Verify safety-sensitive work with qualified guidance.