How does it estimate pipe footage?

It assumes one supply line for each hot and cold connection a fixture needs and one branch drain per fixture, each running the average riser-to-fixture distance you enter, then applies your waste factor. A lavatory adds two supply runs (hot and cold) plus one drain, while a toilet adds one cold supply run plus one drain.

What are water-supply fixture units?

Water-supply fixture units, or WSFU, are a standard demand weighting for each fixture used to size supply piping. Summing the WSFU for all fixtures and reading a Hunter-curve table gives the design flow in gallons per minute, which sets the trunk and main pipe size. The tool totals the WSFU and flags a likely trunk size.

Which fittings does it count?

It uses typical branch-run ratios: about two ninety-degree elbows and one trunk tee per supply line, and about one sanitary tee plus one and a half elbows per fixture on the drain-waste-vent side. These are estimating averages for bidding, not an exact fitting schedule from a drawing.

Is this accurate enough to order materials?

It is a bid-level estimate meant to produce a fast, reasonable material and labor basis. Tight jobs, complex layouts, and final purchase orders should come from a measured takeoff against the actual floor plan and the code-required pipe sizes, using this tool as a sanity check.

What waste factor should I use?

Ten percent is a common allowance for cutoffs, miscuts, and minor rework on a straightforward residential rough-in. Increase it for remodels, tight crawlspaces, or unfamiliar crews, and decrease it for clean new-construction runs where pipe lengths are predictable.

Plumbing Material Takeoff Calculator

Bidding a plumbing rough-in starts with a quick, defensible takeoff: how much pipe, how many fittings, and how big the trunk needs to be. This calculator turns a fixture count and an average run distance into a bid-level material list, so you can price labor and material before measuring every line on the drawing.

How it works

Each fixture contributes supply runs and a drain branch. Fixtures that need both hot and cold add two supply lines; cold-only fixtures such as toilets and hose bibbs add one. Every fixture adds one branch drain. The footage is the run count times the average riser-to-fixture distance, scaled by the waste factor:

supply_ft = (hot+cold lines) x avg_distance x (1 + waste%)
drain_ft  = (fixtures)       x avg_distance x (1 + waste%)

Fittings come from typical branch ratios — roughly two elbows and one trunk tee per supply line, and one sanitary tee plus one and a half elbows per fixture drain. Each fixture also carries a water-supply fixture-unit weighting; summing them gives the total WSFU that drives the trunk-size note.

Tips and example

A small house with two toilets, two lavatories, one tub/shower, a kitchen sink, a dishwasher, a clothes washer, and two hose bibbs at an 18 ft average run and 10 percent waste totals around 22 fixture units and produces roughly a couple hundred feet of supply plus the drain branches, with the trunk note recommending a 1-inch main.

Treat the output as a starting estimate. Tighten it with a measured takeoff for the final purchase order, and always confirm the trunk and branch sizes against the WSFU demand and the plumbing code your jurisdiction enforces.