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Pipe Sizing Calculator (IPC)

IPC Table 604.3 · Water Supply · Fixture Units → Pipe Diameter

When to use: Use to size water supply branches and mains from total fixture unit load per IPC Section 604 and Table 604.3. Enter the total water supply fixture units (WSFU) served by the pipe segment. The calculator applies Hunter's curve to estimate peak demand flow (GPM) and selects the minimum IPC-compliant pipe size. Use for domestic cold and hot water systems, branches, risers, and building mains.

System Parameters
Per IPC Table 604.1
WSFU
Quick Fixture Reference
Lavatory1 WSFU
Water Closet (flush tank)2.5 WSFU
Kitchen Sink1.5 WSFU
Bathtub/Shower1.5 WSFU
Dishwasher1.5 WSFU
Laundry Washer2 WSFU
Minimum Pipe Size
1"
nominal pipe diameter
Results
Total WSFU30 WSFU
Peak Demand (Hunter's curve)28.0 GPM
Minimum Pipe Size (IPC 604.3)1"
References
IPC Section 604 – Water supply sizing
IPC Table 604.1 – Fixture unit values
IPC Table 604.3 – Pipe size by WSFU
Hunter's curve – probability-based peak demand