Plumbing Pipe Sizing Calculator
Determine the correct water supply pipe diameter based on the total fixture units in a building. Uses WSFU (Water Supply Fixture Units) methodology per UPC/IPC standards.
1 WSFU each
1.5 WSFU each
2 WSFU each
2 WSFU each
3 WSFU each
1.5 WSFU each
2 WSFU each
1.5 WSFU each
2.5 WSFU each
0 WSFU each
Results
Total Fixture Units
13.5
WSFU
Estimated Peak Flow
13.5
GPM
Main Supply Pipe
1"
diameter
How to Use This Calculator
Enter the number of each type of plumbing fixture in the building. The calculator totals the Water Supply Fixture Units (WSFU) and recommends a main supply pipe diameter. This is based on standard residential pressure conditions (40-80 PSI). For long runs, high-rise buildings, or low-pressure situations, upsize by one pipe diameter.
Formula Used
Total WSFU = Sum of (Fixture Count × Fixture Unit Value). Pipe size selected from UPC/IPC sizing tables based on total WSFU.
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Disclaimer
This calculator is for estimation purposes only. Results may vary based on local conditions, materials, and building codes. Always consult a licensed professional before making decisions based on these calculations. MyContractorTools is not responsible for any errors or omissions.