Enter fixture pipe runs and counts to get pipe footage with fittings and a DFU-based minimum drain diameter, checked against verified IPC reference rows.
Plumbing estimating on this page covers pipe run footage with an editable fitting allowance, and drain sizing by total fixture units (DFU) against IPC reference tables. It is the same Plumbing calculator available on its own page, just presented with the informational context below.
Measure each fixture’s drain run along the routed path from the fixture to where it joins the branch or building drain, not a straight-line distance. Enter each fixture type separately with its own run length and count, since fixture units and fitting needs differ by fixture.
A Drainage Fixture Unit (DFU) is a standardized load value assigned to each fixture type by the plumbing code, used to size drain and vent piping. A water closet, for example, carries more DFU load than a lavatory. Total DFU load, plus the pipe context (building drain vs. horizontal branch), determines the minimum pipe diameter this calculator checks against.
Enter each fixture's run length and count, then pick a pipe context and a diameter to check. Results update as you type, with no Calculate button.
Pipe footage with fittings, plus DFU-based drain diameter sizing.
Enter a fixture and a run length to size this drain.
You'll need
DFU load values and drain-capacity rows in this calculator are sourced from IPC 2021 Table 709.1 (fixture unit values) and Tables 710.1(1) and 710.1(2) (drain capacity by pipe diameter). Only the fixture types, pipe contexts, and capacity rows documented in those tables are supported — this calculator does not extrapolate to fixtures or local amendments outside that verified dataset.
When a water closet is part of the run, a 3 inch minimum drain diameter is enforced regardless of the DFU-calculated minimum, matching the code’s water closet minimum requirement. Always verify the locally adopted code before installation, since jurisdictions frequently amend IPC base tables.
Plumbing's pipe footage and DFU sizing don't have a natural second calculator to chain them to in this release, unlike Roofing's rafters-to-shingles-to-sheathing flow. This page still gives Plumbing the same informational, SEO-focused treatment as the multi-calculator trades.
No. Verify the locally adopted code, since jurisdictions frequently amend IPC base tables.
Only fixtures with verified IPC Table 709.1 reference values are included. Unsupported fixtures are not guessed.
When a water closet is served, the calculator enforces a minimum 3 inch drain diameter regardless of the calculated DFU-based minimum.
General reference only. Verify local requirements before installation.