Work out how much
before you buy it.
Concrete, lumber, wire, filament — work out how much you need before you buy it. Put the numbers in and you get the quantity, the waste allowance and the working behind it, in a form you can copy into an order.
Concrete & Masonry
5See all →Concrete Slab Calculator — Bags and Cubic Yards for a Slab, Footing or PierCubic yards and bag count for a slab, footing or padBrick and Block Calculator — How Many Bricks or CMU per Square Foot of WallUnit count, mortar and sand for a brick or CMU wallMortar Mix Calculator — Bags of Type N, S or M for Laying and RepointingMortar volume for laying or repointing, as bags or as portland, lime and sandRetaining Wall Block Calculator — Courses, Caps, Base Gravel and Drain StoneBlock count, courses, caps and gravel for a segmental retaining wallPaver Patio Calculator — Pavers, Base Gravel and Joint Sand by PatternPaver count, base gravel, bedding sand and joint sand for a patio or walkway
Lumber & Framing
8See all →Wood Movement Calculator — Seasonal Width Change and the Gap a Joint NeedsSeasonal width change by species and grain, and the slot or gap to allow for itWood Finish Coverage Calculator — How Much Stain, Oil, Poly or Shellac to BuyQuantity of stain, oil, polyurethane or shellac for an area and a number of coatsGlue and Clamp Calculator — Glue Quantity, Clamp Count, Spacing and PressureGlue quantity for a glue-up, plus how many clamps, how far apart and how hardShelf Sag Calculator — Deflection by Span, Thickness, Material and LoadPredicted deflection of a shelf, and whether it clears an acceptable-sag limitBoard Foot Calculator — Nominal vs Actual, Quarter Sizes and Lumber CostBoard feet and cost for dimensional lumber and rough hardwoodStud Wall Framing Calculator — Studs at 16 or 24 On Center, Plates and HeadersStuds, plates, headers and board feet for a framed wallDeck Board Calculator — Boards, Linear Feet, Joists and FastenersDeck boards, lineal feet, fasteners and joist count for a deck surfacePlywood Sheet Calculator — How Many 4x8 Sheets and How Much OffcutSheets of plywood, OSB or MDF for a given area, with offcut left over
Paint, Tile & Flooring
12See all →Curtain Size Calculator — Panel Width, Length and Fabric Yardage With FullnessFinished panel width and length, panel count and yardageDrywall Sheet Calculator — Sheets, Screws, Tape and Joint Compound for a RoomSheets, screws, tape and mud for walls and ceilingInsulation Calculator — Batts or Blown Bags for a Target R-ValueBatt count or bags of blown, and the depth an R-value needsLighting Layout Calculator — Recessed Light Spacing, Count and Lumens per RoomLumens for the room, fixture count and the spacing gridRoofing Squares Calculator — Shingle Bundles, Starter, Ridge Cap and NailsSquares, bundles, starter, ridge cap and nails for a shingle roofRoof Pitch Calculator — X-in-12 to Degrees, Percent and the Slope MultiplierConvert pitch to degrees, percent and the area multiplierGutter and Downspout Sizing Calculator — 5 in or 6 in K-Style and How Many LeadersGutter size, downspout count and spacing from roof area and rainfallRoof Underlayment and Drip Edge Calculator — Rolls, Sticks and Ice BarrierUnderlayment rolls, drip edge sticks and ice barrier coverage
Electrical
4See all →Voltage Drop Calculator — Percent Drop Over a Run in Copper or AluminumVolts and percent lost over a run, for copper or aluminiumWire Size Calculator — AWG for a Given Load, Distance and Voltage Drop TargetConductor size a run needs to hold a target voltage dropCircuit Load Calculator — Amps on a Branch Circuit and the 80 Percent RuleAdd up the loads on a branch circuit against the breaker ratingGenerator Sizing Calculator — Running Watts vs Starting Surge by ApplianceRunning watts and starting surge for a list of appliances
Plumbing & Water
4See all →Pipe Volume Calculator — Gallons of Water in a Run of Copper, PEX or PVCGallons, weight and flush time for a length of pipeWater Flow Pressure Drop Calculator — Friction Loss and Velocity in a Pipe RunFriction loss in psi and velocity in ft/s over a runPool Volume Calculator — Gallons in a Rectangular, Round or Oval Pool or TankGallons and turnover time for a pool, pond or tankDrain Slope Calculator — Fall Per Foot for a Waste Line or French DrainTotal fall and invert elevations for a sloped drain run
Yard & Garden
8See all →Sod and Grass Seed Calculator — Rolls, Pallets and Pounds of Seed by Lawn SizeSod rolls, pallets and pounds of seed for a lawn areaFertilizer Calculator — Pounds of Product From an N-P-K Analysis and a Nitrogen TargetPounds of product from the bag analysis and a lb-N targetFirewood Cord Calculator — Cords, Face Cords, Price per Cord and Heat ValueCords and face cords from stack size, with price and heat valueIrrigation Zone Calculator — Heads per Zone, Zone Count and Sprinkler Run TimeHeads per zone, zone count and run time from GPM and head spacingMulch Calculator — Cubic Yards and 2 Cu Ft Bags by Bed Size and DepthCubic yards, bag count and bulk order for bedsTopsoil Calculator — Cubic Yards, Bags and Tons With a Settling AllowanceCubic yards, bags and approximate tons of soil or garden mixGravel Driveway Calculator — Yards and Tons per Layer With CompactionCubic yards and tons of gravel by layer, with compactionFence Post Calculator — Post Count, Spacing and Concrete per HolePost count, rails or panels, and concrete per hole
3D Printing
2See all →Filament Cost Calculator — Cost per 3D Print Including Power and FailuresWhat a 3D print actually costs — filament, power, wear and failuresResin Print Cost Calculator — Cost per Part Including IPA, FEP and FailuresCost per part for MSLA resin printing, including IPA, FEP and failures
Shop Math
18See all →CFM Calculator from Air Changes per Hour — Fan Sizing for a Bathroom, Kitchen or ShopRequired CFM from room volume and a target ACH, and the reverseDuct Size Calculator — Round and Rectangular Duct from CFM, Velocity or Friction RateRound diameter and equivalent rectangular sizes from CFMDust Collection Calculator — CFM Per Machine, Duct Velocity and Whether Your Collector Is EnoughRequired CFM, transport velocity check and system resistanceDehumidifier Size Calculator — Pints Per Day for a Basement, Crawlspace or ShopPints per day from area, dampness level and conditionsMoving Truck Size Calculator — Cubic Feet, Truck Length and How Many TripsCubic feet of household goods, truck length, and trips for a smaller truckStorage Unit Size Calculator — Square Footage, Unit Size and Monthly CostSquare footage and unit size from a volume, with stacking and an aisleMoving Box Calculator — How Many Small, Medium and Large Boxes, With Tape and PaperBox counts by size, plus tape, paper, bubble wrap and costFurniture Fit Calculator — Will It Fit Through the Door, Hallway and Stair TurnDoorway, tilt angle, corner turn and the diagonals that govern
Metal & Welding
4See all →Metal Weight Calculator — Steel, Stainless, Aluminum and Brass Bar, Tube, Plate and AngleWeight of plate, bar, tube and angle in steel, stainless, aluminum, brass or copperBend Allowance Calculator — Flat Pattern, Bend Deduction and K-Factor for Sheet MetalFlat blank length from thickness, bend radius, angle and K-factorTap Drill Size Calculator — Tap and Clearance Drills for UNC, UNF and Metric ThreadsTap drill and clearance drill for any common thread, at the engagement you chooseWeld Cost Calculator — Deposited Metal, Filler, Gas and Labor per JointDeposited weld metal, filler consumed, gas used and cost per joint
Vehicle & Garage
4See all →Tire Size Comparison Calculator — Diameter, Circumference and Speedometer ErrorCompare two tire sizes and the speedometer error between themGear Ratio Speed Calculator — MPH from RPM, Axle Ratio and Tire DiameterRoad speed and cruising rpm from gearing and tire sizeTowing and Payload Calculator — What Is Left After Passengers, Cargo and Tongue WeightPayload left over once passengers, cargo and tongue weight are countedOil Change Cost Calculator — Cost per Change, per Year and per MileCost per oil change, per year and per mile, comparing two options
Solar & Off-Grid
4See all →Solar Panel Array Sizing Calculator — Array kW, Panel Count and Roof Area for a Daily LoadArray kW and panel count for a daily kWh loadBattery Bank Sizing Calculator — Amp-Hours, Usable kWh and Series/Parallel LayoutAmp-hours and battery count for a backup or off-grid bankInverter and Charge Controller Sizing Calculator — Continuous Watts, Surge and MPPT vs PWM AmpsInverter continuous and surge watts, plus controller ampsSolar Payback Calculator — Years to Break Even and 25-Year Savings on a Solar SystemBreak-even years and lifetime savings on a solar system
JSON Formatter and Validator — Pretty Print, Minify, Find the Syntax ErrorIndent, minify and validate JSON, with the error lineJSON Diff — Compare Two JSON Documents by Path, Not by LineAdded, removed and changed keys between two JSON documentsYAML to JSON Converter — Both Directions, with Indentation Errors LocatedConvert YAML to JSON and back, in the browserCSV to JSON Converter — RFC 4180 Quoting, Tabs and Semicolons, Both DirectionsCSV or a pasted spreadsheet to JSON, and backJSON to TypeScript — Generate Interfaces from a Sample ResponseInterfaces or type aliases inferred from a JSON sampleAPI Response Viewer — Explore JSON by Path, Type and NullEvery value in a JSON response, with its path and typeBase64 Encoder and Decoder — UTF-8 Safe, With the URL-Safe AlphabetEncode and decode Base64 without mangling UTF-8URL Encoder and Decoder — Percent Encoding for Query Values and Whole URLsPercent-encode a single value or a whole URL
What this is
Most material questions have a clean answer that nobody writes down plainly. How many bags of concrete for a four-inch slab. Whether 14 gauge is enough over a forty-foot run. How much filament a print actually eats. The calculators here give the number and show the arithmetic, including the assumption that is most likely to be wrong for your job, so you can change it rather than guess again.
Nothing is uploaded. Everything runs in your browser, there is no sign-up, and each page states the range its figures vary over instead of quoting a false precision.