Sizing and flowIPC 604
Supply and drainage sizing, dimensioned and sourced to the code table it came from.
6 tools · 5 guides · 2 compare
Every number on the job, dimensioned
Pipe sizing, drain slope, fixture units and installed cost bands for plumbing contractors. Every figure carries the code section or the source it came from and the date it was read.
Isometric
Calculators
18 of them, all working in the browser, none of them asking for an email.
Pipe size calculatorIPC 604
Most usedOpen
Size a water supply run from fixture units, developed length and available pressure.
1/2"–2"IPC 604
Drain slope calculatorIPC 604
Fall over a run at 1/8, 1/4 and 1/2 inch per foot, with the code minimum for the size.
1-1/4"–8"IPC 704
Fixture unit calculatorIPC 604
Total WSFU and DFU for a fixture list, both codes side by side.
WSFUDFU
Gas pipe size calculatorIPC 604
Schedule 40 and CSST sizing by BTU load and longest length.
NFPA 54in. w.c.
Water pressure calculatorIPC 604
Static head, elevation loss and friction loss to a PSI at the fixture.
PSIft head
Hot water wait time calculatorIPC 604
Seconds to hot, gallons in the line and water run to drain, by pipe and flow.
CuPEX · CPVC · IPC 607.2
Water heater cost calculatorUSD 2026
Tank size, fuel, permit and haul-away into one installed band.
40–80 galUSD
Repipe cost calculatorUSD 2026
Fixtures, stories and material into labour hours and a material band.
PEXCPVC · Cu
How this site is built
Sourced
Every figure carries its source
Code tables are quoted with the section and edition. Wages come from BLS. Cost bands are ranges read from vendor listings, with the date they were read written into the page source.
Dimensioned
Numbers are units, not adjectives
A size, a GPM, a PSI, a fixture unit, a slope, a code section. Every one of them set in mono with its unit annotated, so a figure can be read off a page and used on site.
Yours
The rates in the calculators are your own
No national shop rate is asserted anywhere. Labour is your hours at your rate; material is what your supplier charged you today. Nothing here pretends to know your market.
Four pillars
Costs and estimatingUSD 2026
Installed bands from live vendor and government sources, with the estimating maths behind them.
5 tools · 9 guides · 1 compare
Code and permitsIPC · UPC
IPC and UPC in plain language, plus the permit and inspection path for a residential job.
3 tools · 5 guides · 3 compare
Fixtures and repairsService
Service and rough-in work: sizing a heater, clearing a line, setting a valve at the right height.
4 tools · 5 guides · 5 compare
Guides
24 of them, and 11 side-by-side comparisons under Compare.
Pipe size chartNominal versus actual diameter for copper, PEX, CPVC, PVC and steel.8 minHow pipe size is measuredWhy nominal never matches your caliper, and how to identify a line on site.7 minDrain pipe slope per footCode minimums by size, the too-steep myth, and how to shoot a grade.8 minPlumbing fixture units explainedWSFU and DFU, what they actually count, and a worked house.9 minHow to check water pressureThe gauge test, static vs flowing, the overnight spike, and what each reading means.8 minWater heater replacement costInstalled bands by type and what actually moves the number.10 minTankless water heater costUnit, gas upsize, venting and condensate — plus the payback maths.10 minSewer line replacement costOpen cut versus pipe burst versus CIPP, per foot, with restoration.9 min
All 24 guidesComparisons
Materials, pumps and codes set against each other on the factors that decide a job.
PEX vs copperBore, freeze behaviour, failure modes and the sizing trap the swap creates.comparePEX-A vs PEX-BHow each is made, which fittings it takes, kinks, bends and printline codes.compareTank vs tankless water heaterInstall cost, running cost, recovery, lifespan and venting.compareIPC vs UPCAdoption by state and the clauses that genuinely differ on a house.compareABS vs PVC for DWVTemperature rating, joining method, code acceptance and cost.compareCast iron vs PVC drain pipeNoise, firestopping, expansion and the legal transition joint for repairing old iron.compareP-trap vs S-trapSiphonage, code status and the retrofit path when you find one.compareCopper vs CPVC vs PEX for a repipeThe whole-house repipe decision: labour, wall access, risk and inspections.comparePedestal vs submersible sump pumpMotor in air or under water: cooling, pit size, switches, backups and the RPZ rule.compareJet pump vs submersible well pumpSuction lift, 2-wire vs 3-wire, tank settings and what a pull involves.compareBest water heater brandsFive makers' tank, tankless and heat pump lines, how each is sold, and what the warranty covers.compare
All 11 comparisonsKeep the code book handy.
Every table on this site is dimensioned, sourced and dated. Bookmark the calculator you use most and it will be there on the next callout.
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