Pipe Size Calculator
Find the right water supply pipe size for your project
Sum of WSFU
Static pressure at meter
From meter to farthest fixture
Main Supply Line
—
inches
Branch Lines
—
inches
Peak Flow Rate
—
GPM
How to Use This Calculator
Our pipe size calculator follows UPC and IPC guidelines to recommend the right pipe diameter.
- Add up WSFU for all fixtures
- Measure static pressure at meter
- Determine longest pipe run
- Enter specifications
- Consider future additions
AI Insights
Smart analysis for your project
Smart Estimates
Our AI cross-references material costs, regional pricing, and project complexity for more accurate estimates.
Waste Optimization
AI-calculated waste factors based on project type, not flat percentages. Saves 5-15% on material costs.
Best Practices
Recommendations derived from building codes, contractor data, and thousands of completed projects.
Calculation Formula
Based on UPC/IPC tables:
Flow rate from WSFU conversion
Pipe size from flow rate x pressure x length
Frequently Asked Questions
What size pipe for a main water line?
Most homes use 3/4" or 1" copper/PEX for main supply. Size depends on fixtures and pressure.
What are WSFU?
Water Supply Fixture Units: bathroom faucet = 1, shower = 2, toilet = 2.5, kitchen sink = 1.5, washing machine = 4.