Pipe Sizing Calculator

Pipe Sizing Fundamentals

Correct pipe sizing balances flow velocity, pressure drop, and cost. Too small a pipe causes high velocity (noise, erosion, excessive pressure loss). Too large wastes material and money.

Velocity Guidelines

• Residential (quiet): 4–5 fps recommended to minimize water hammer and noise.
• Standard: 5–8 fps is the most common design range.
• Commercial: Up to 10 fps acceptable for main supply lines.
• Never exceed 10 fps to prevent erosion and excessive noise.

Material Considerations

PEX and PVC have smoother interiors (higher C-factor) resulting in less friction than copper. However, copper is more rigid and better suited for exposed runs. CPVC handles hot water better than PVC but has a slightly smaller internal diameter than PVC at the same nominal size.