Plumbing Calculators
Pipe sizing, flow, drainage, and capacity.
Electrical
10 TOOLSNEC code checks and electrical design calculators.
- VDVoltage Drop CalculatorNEC Table 9 voltage drop with the 3% branch check.
- AMPWire Ampacity & Derating CalculatorDerated ampacity per NEC Table 310.15(B)(16).
- FILLConduit Fill CalculatorMixed-conductor fill vs. 53 / 31 / 40% limits.
- BOXBox Fill CalculatorNEC 314.16 volume vs. conductor & clamp counts.
- FLAMotor FLA CalculatorFLA from HP, voltage & phase per NEC tables.
- kVATransformer Sizing CalculatorkVA and amps, single- and three-phase.
- LOADService & Load CalculatorDwelling & commercial loads to size the service.
- BENDConduit Bending CalculatorOffset & saddle multipliers, shrink & marks.
- ΩOhm's Law & Power CalculatorVolts, amps, ohms & watts from any two values.
- GENGenerator Sizing CalculatorRunning & starting kW with motor inrush.
Plumbing
7 TOOLSPipe sizing, flow, drainage, and capacity.
- VOLPipe Volume & Capacity CalculatorGallons per foot & total fill by pipe size.
- ¼"Drainage Pipe Slope CalculatorFall over a run and the minimum-grade check.
- PSIWater Pressure Loss CalculatorFriction loss through pipe & fittings at GPM.
- DFUFixture Unit CalculatorDFU / WSFU totals from fixture counts.
- SIZEPipe Sizing CalculatorDiameter from flow, length & allowable loss.
- TANKTank Volume CalculatorCylinder, rectangle & oval capacity in gallons.
- GPMGPM Flow Rate CalculatorGPM from pipe size & velocity — or the reverse.
HVAC & Mechanical
6 TOOLSAirflow, loads, duct sizing, and refrigeration.
- DUCTDuct Size CalculatorRound & rect sizes from CFM and friction rate.
- CFMCFM & Airflow CalculatorCFM from room volume and target air changes.
- BTUBTU & Heat Load CalculatorBTU/hr load from area, climate & construction.
- TONCooling Tonnage CalculatorBTU/hr to tons of cooling, and back.
- ESPStatic Pressure CalculatorTotal ESP from duct, coil & filter losses.
- REFRefrigerant Line Charge CalculatorAdded charge for line length past pre-charge.
Carpentry & Framing
6 TOOLSLumber, framing, stairs, rafters, and decking.
- BDFTBoard Foot CalculatorBoard feet & cost from nominal size and count.
- STUDStud & Framing CalculatorStuds, plates & lineal feet from wall length.
- STRStair CalculatorRiser, tread & stringer layout from total rise.
- RFTRRafter & Roof Pitch CalculatorRafter length & cuts from pitch and span.
- JOISTJoist Span CalculatorAllowable spans by species, size & spacing.
- DECKDecking CalculatorBoards, joists & fasteners from deck size.
Concrete & Masonry
6 TOOLSVolume, rebar, block, brick, and mortar takeoffs.
- CONCConcrete Volume CalculatorYards for slabs, footings & columns, with bags.
- REBRRebar Weight & Spacing CalculatorBar count, length & weight from grid spacing.
- CMUBlock / CMU CalculatorBlock count, courses & mortar for a wall.
- BRCKBrick CalculatorBrick count & mortar from wall area and size.
- MRTRMortar & Grout CalculatorBags of mortar or grout for block & cell fill.
- FOOTFooting CalculatorVolume & rebar for continuous and pad footings.
Earthwork & Site
6 TOOLSExcavation, cut & fill, trenching, and aggregate.
- EXCVExcavation Volume CalculatorBank yards from area & depth, with swell.
- C/FCut & Fill CalculatorNet import / export from average cut & fill.
- TRCHTrench Volume CalculatorSpoil, bedding & backfill for a trench run.
- AGGAggregate & Gravel TonnageTons of gravel, sand or base from area & depth.
- CMPTCompaction CalculatorLoose vs. compacted volume and lift counts.
- SWELSoil Swell & Shrink CalculatorBank, loose & compacted volume conversions.
Roofing & Exterior
6 TOOLSRoof area, pitch, shingles, panels, and gutters.
- AREARoof Area & Pitch CalculatorTrue area & squares from footprint and pitch.
- SHGLShingle & Bundle CalculatorBundles & squares, plus starter and ridge.
- PTCHRoof Pitch MultiplierPitch to angle, slope factor & multiplier.
- UNDRUnderlayment CalculatorRolls of felt or synthetic from area & overlap.
- PNLMetal Roofing Panel CalculatorPanels & lineal feet from roof and panel width.
- GUTRGutter & Downspout CalculatorGutter feet & downspouts from drainage area.
Drywall, Paint & Finishes
6 TOOLSDrywall, paint, tile, flooring, and insulation.
- DRYDrywall Sheet CalculatorSheets, screws & tape from wall & ceiling area.
- PNTPaint Coverage CalculatorGallons per coat from area and spread rate.
- MUDJoint Compound CalculatorMud boxes & tape footage by finish level.
- TILETile CalculatorTile count, thinset & grout from area and waste.
- FLRFlooring CalculatorBoxes & underlayment from room area and waste.
- RInsulation CalculatorBatts or blown bags from area and R-value.
General & Shared
7 TOOLSCross-trade field math, takeoffs, and estimating helpers.
- YD³Construction CalculatorConcrete yards, aggregate tons & unit conversions.
- FT²Square Footage CalculatorArea & perimeter with multi-room totals.
- 3·4·5Right-Angle (3-4-5) CalculatorDiagonals & hypotenuse to square up corners.
- %Slope & Grade Calculator% grade, ratio, degrees & rise/run conversions.
- %↑Markup & Margin CalculatorMarkup vs. margin & price to a target profit.
- HRSLabor & Crew Cost EstimatorBurdened crew cost per hour and per day.
- FUELEquipment Fuel Cost CalculatorFuel burn & cost by machine and run hours.
Market Data
3 TOOLSLive-ish prices and trends for the materials you buy.
ABOUT THESE TOOLS
Plumbing design comes down to moving the right volume of water at the right velocity with enough pressure left at the fixture — and draining it away at a grade that keeps solids moving. These calculators handle that math: fixture-unit totals (DFU and WSFU) from fixture counts, recommended pipe diameter from flow and allowable pressure loss, friction loss through pipe and fittings at a given GPM, velocity-to-flow conversions, drainage fall over a run from slopes like ¼ inch per foot, and the volume held in pipe runs and tanks.
The sizing conventions follow the model plumbing codes — the Uniform Plumbing Code (UPC) and International Plumbing Code (IPC) both size drainage and water distribution from fixture-unit loads and set minimum drainage slopes by pipe diameter. Which one governs, and with what local amendments, depends on your jurisdiction, so treat these results as working numbers to verify against the adopted code and your inspector. Each tool is free, browser-based, and requires no login — quick enough to run from the trench or the supply-house counter.
Run your whole job on the same numbers
These NORDIX tools are a taste of the full platform — bid pipeline, estimating, and job costing that carry your numbers from the first bid to the final invoice.
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