Drainage Fixture Units Calculator
Calculate total DFUs for drain pipe sizing. Free, instant.
How to Use Drainage Fixture Units Calculator
1
Enter fixture counts.
2
Get total drainage fixture units.
3
Use to size drain pipes per code.
Frequently Asked Questions
How do DFUs relate to pipe size?
A 3" drain handles up to 20 DFUs, 4" handles up to 160 DFUs.