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Pipe Sizing Calculator

Look up minimum supply pipe diameter for a given fixture unit load per IPC Table E103.3.

Total supply fixture units for the pipe segment

Traditional choice; higher cost, long lifespan, approved everywhere

Minimum Pipe Diameter1.25in

Per IPC Table E103.3(1) -- applies to copper, PVC, and PEX supply pipe

IPC Table E103.3 Quick Reference

Fixture UnitsMin Pipe Size
1 FU1/2 inch
2-4 FU3/4 inch
5-8 FU1 inch
9-14 FU1-1/4 inch
15-24 FU1-1/2 inch
25-42 FU2 inch
43-60 FU2-1/2 inch
61-96 FU3 inch
97-256 FU4 inch

Reference: IPC Table E103.3(1) -- Demand versus required size of water-service and water-distribution pipe

For reference only. Verify with your local building code and a licensed professional before making decisions.

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