Construction, Woodworking & DIY Calculators

70 free calculators for the workshop and the job site: cut lists and plywood layouts, wood movement, wood weight and equilibrium moisture content, miters, dovetails and mortise and tenon joints, shelf sag, board feet and lumber cost; tap drills, clearance holes, tapped hole depths, drill speeds, bolt circles, countersinks and sheet metal bend allowance; epoxy pours, log scale, arcs and taper jigs; lathe speeds, CNC router feeds, band saw blades, pulleys and segmented bowl rings; cardboard box templates and project pricing; concrete, block and brick; framing, roofs, stairs, decks and fences; drywall, paint, wallpaper, tile, flooring and insulation; gravel, topsoil and mulch. Every calculator shows its formula, a worked example with the numbers, notes on waste and limits, a short FAQ, and the sources it relies on: building codes such as the International Residential Code, the USDA Wood Handbook, industry associations such as NCMA, BIA and the American Wood Council, US Army and FAA training manuals, extension publications and manufacturer data sheets.

Looking for species data? The wood species database lists hardness, density, strength, shrinkage and decay resistance for 192 woods from the USDA Wood Handbook, with a Janka hardness chart.

Reference charts and code guides

Charts and guides that go with the calculators: sizes, code requirements in plain words, and the arithmetic behind them. For bolts, taps and fasteners see the thread and fastener charts. The same guides are grouped by rule book (IRC, OSHA, ADA, ventilation and materials) on the building code and safety guides page.

Planning tools, not approvals. The footing, deck joist span and deck beam span calculators give planning estimates from published span tables and prescriptive methods. Local codes, site conditions and loads vary, so confirm structural sizes with your building department or an engineer before you build.

Woodworking & Lumber

Cut lists for boards and plywood, wood movement, miters, dovetails, arcs and taper jigs, shelf sag, screws, glue, finish and epoxy, board feet, log scale and lumber cost.

Board Foot Calculator: Board feet for any number of boards, with optional price per board foot.
Lumber Cost Calculator (Per Piece, Board Foot or Linear Foot): Total cost of a lumber list, and what each board works out to per board foot and per linear foot.
Cut List Optimizer (Boards, Kerf and Waste): Fits your parts onto boards of the lengths you have, allowing for the saw kerf, and draws the layout with its waste.
Plywood Cut Calculator (Sheet Goods Layout Optimizer): Lays your panel parts out on 4 x 8 or any other sheet, with kerf, and shows how many sheets you need and the waste.
Wood Movement Calculator (Shrinkage and Expansion by Species): How much a board will shrink or swell across the grain between two moisture contents, from USDA Wood Handbook shrinkage values.
Miter Angle Calculator (Corners, Polygons and Compound Miters): Saw settings for any corner or polygon, plus compound miter and bevel angles for crown molding and sloped-sided boxes.
Dovetail and Box Joint Layout Calculator: Marks out evenly spaced tails and pins, or box joint fingers, across a board of any width, with an SVG drawing to follow.
Shelf Sag Calculator (Deflection by Span, Thickness and Material): Predicts how far a loaded shelf will sag from beam deflection formulas and published wood stiffness, and says whether it will show.
Screw and Nail Size Calculator (Length, Gauge and Pilot Holes): Picks a screw length and gauge or a nail penny size for the boards you are joining, with pilot, clearance and countersink sizes.
Wood Glue Coverage Calculator (Ounces per Joint Area): How much PVA glue a glue-up needs, in ounces and millilitres, from the manufacturer’s spread rate and your joint area.
Wood Finish Coverage Calculator (Polyurethane, Stain, Oil): Quarts or gallons of polyurethane, stain, oil, shellac or lacquer for a project, from the area, number of coats and coverage rate.
Equilibrium Moisture Content Calculator for Wood (EMC): The moisture content wood settles at for a given temperature and relative humidity, with the USDA Wood Handbook equation and targets for indoor and outdoor wood.
Wood Weight Calculator (Lumber Weight by Species and Moisture): Weight of boards, beams and slabs for 190 species at any moisture content, from USDA Wood Handbook specific gravity and shrinkage data.
Epoxy Resin Calculator (River Table, Deep Pour and Table Top): How much epoxy a river table, mold or table-top flood coat needs, in gallons, quarts, ounces and litres, split into resin and hardener, with weight and number of pours.
Log Board Foot Calculator (Doyle, Scribner and International Rules): Board feet in a sawlog by the Doyle, Scribner and International 1/4 inch log rules, from small-end diameter and length.
Arc Radius Calculator (Radius From Chord and Rise, With Layout): The radius of an arch or curve from its width and height, the arc length, and offsets to lay the curve out on a board.
Taper Jig Calculator (Taper Angle and Jig Offset for Legs): Taper angle, taper per foot and the jig opening for a table saw or band saw taper jig, for one-sided and two-sided leg tapers.

Concrete & Masonry

Slabs, post holes and form tubes, steps, block and brick walls, core fill, mortar, rebar and footings.

Post Hole & Sonotube Concrete Calculator: Bags or yards of concrete for fence and deck post holes, piers and form tubes.
Concrete Steps Calculator: Concrete volume and bags for a flight of solid concrete steps with a top landing.
Cinder Block Calculator (CMU Block Count): How many concrete blocks for a wall, using the NCMA estimating method.
Block Fill Calculator (Grout for CMU Cores): Grout or core-fill volume for hollow block walls, solid or partly grouted (NCMA TEK 4-2A).
Mortar Calculator for Block Walls: Bags of mortar mix, or masonry cement and sand, to lay concrete block (NCMA TEK 4-2A).
Rebar Calculator for Slabs (Grid Spacing & Quantity): Bars, linear feet, weight and 20-ft sticks for a rebar grid in a slab or pad.
Footing Calculator: Concrete Volume & Deck Footing Size Estimate: Concrete for wall footings, and a planning estimate of deck pad footing size from load and soil bearing. (planning estimate)
Concrete Slab Calculator (Cubic Yards, Bags and Cost): Cubic yards, cubic metres and bags of premix for a slab, patio, shed base or footing strip, with waste.
Brick Calculator (Bricks and Mortar for a Wall): Bricks per square foot for modular, queen and king sizes from BIA tables, mortar volume and bags, with waste.

Framing, Roofs, Decks & Fences

Studs, rafters, roof pitch, trusses, shingles, stairs, deck joists, beams and boards, and fence materials.

Wall Stud Calculator (Studs, Plates & Headers): Studs, plates and extra framing for a wall at 12, 16 or 24 in on center.
Rafter Length Calculator (Common Rafters): Common rafter length from span and pitch, with ridge allowance and overhang.
Roof Pitch Calculator (Rise and Run to Pitch): Pitch, angle, slope percentage and slope factor from any rise and run you can measure.
Roof Pitch to Degrees Converter (and Degrees to Pitch): Convert x/12 roof pitch to degrees and back, with a full conversion table.
Roof Truss Calculator (How Many Trusses): Number of roof trusses for a building length at 24 in or 16 in on center.
Stair Calculator: Rise, Run and Stringer Length: Number of risers, riser height, tread run, stringer length and IRC checks from total rise.
Deck Joist Span Calculator (IRC Table R507.6 Estimate): Maximum deck joist span for species, size and spacing from the IRC span table. (planning estimate)
Deck Beam Span Calculator (IRC Table R507.5 Estimate): Maximum deck beam span between posts for beam size, species and joist span. (planning estimate)
Deck Board Calculator (Boards, Linear Feet and Screws): How many deck boards, linear feet and screws a deck needs from its size, board width, gap and joist spacing.
Fence Calculator (Posts, Rails, Pickets and Concrete): Posts, rails, pickets and bags of concrete for a wood fence from its length, post spacing and picket size.
Roofing Calculator (Squares, Shingle Bundles and Underlayment): Roof area from the footprint and pitch, then squares, shingle bundles, underlayment rolls and ridge cap with waste.

Drywall, Paint, Tile & Interior Finishes

Drywall sheets and mud, paint, wallpaper, tile and grout, flooring, insulation, siding and trim.

Joint Compound Calculator (Drywall Mud & Tape): Gallons and pails of drywall joint compound, plus joint tape, for any wall and ceiling area.
Siding Calculator (Squares of Siding): Wall and gable area in squares of siding, less windows and doors, plus waste.
Baseboard & Trim Calculator (Linear Feet and Pieces): Linear feet and number of 8, 12 or 16 ft pieces of baseboard, crown or chair rail.
Tile Calculator (Tiles, Boxes, Grout and Thinset): Number of tiles and boxes for a floor or wall, plus pounds of grout from the tile industry joint formula and bags of thinset.
Flooring Calculator (Square Feet, Waste, Boxes and Cost): Square feet of hardwood, laminate, vinyl plank or carpet with the right waste allowance, in boxes and dollars.
Drywall Calculator (Sheets, Screws, Mud and Tape): Sheets of drywall for walls and ceiling by sheet size, plus screws at USG spacing, joint compound and tape.
Paint Calculator (Gallons for Walls and Ceilings): Gallons and quarts of paint for a room from its size, doors and windows, coats and the coverage on the can.
Wallpaper Calculator (Rolls Needed with Pattern Repeat): Rolls of wallpaper for a room from wall height, perimeter, roll size and pattern repeat, counting whole drops per roll.
Insulation Calculator (R-Value, Thickness and Batts Needed): R-value from thickness (or the thickness for a target R) by material, and how many batts, rolls or bags cover the area.

Site & Landscape

Gravel and crushed stone, topsoil, fill dirt, mulch, sand, asphalt and pavers with their base, in yards and tons.

Gravel & Crushed Stone Calculator (Yards and Tons): Cubic yards and tons of gravel or crushed stone for a driveway, path, pad or base.
Fill Dirt Calculator (Cubic Yards and Tons): Fill dirt for a low spot, pad or slope: cubic yards and tons, with a compaction allowance.
Sand Calculator (Yards, Tons and Bags): Sand for paver bedding, a sandbox or backfill: cubic yards, tons and bags.
Asphalt Calculator (Tons of Hot Mix): Tons of hot-mix asphalt for a driveway or patch from area and compacted thickness.
Paver Calculator (Pavers, Base Gravel & Bedding Sand): Pavers, compacted base and bedding sand for a patio, walk or driveway (ICPI Tech Spec 2).
Mulch Calculator (Cubic Yards and Bags): Cubic yards and 2 or 3 cu ft bags of mulch for beds at any depth, with approximate weight and cost.
Topsoil Calculator (Cubic Yards, Tons and Bags): Cubic yards, tons and bags of topsoil or garden soil for lawns, beds and raised beds from area and depth.

Measuring & Conversions

Square footage of any room shape and tape-measure fractions to decimals and millimetres.

Fraction to Decimal Inch Calculator (and Decimal or mm to Fraction): Converts tape-measure fractions to decimal inches and millimetres, and decimals or millimetres back to the nearest 16th, 32nd or 64th.
Square Footage Calculator (Rooms, Circles, Triangles and L-Shapes): Area of rectangles, L-shaped rooms, circles, triangles and trapezoids in square feet, yards and metres, with feet-and-inches input.

Threads, Taps, Holes & Metalwork

Tap drill sizes, clearance holes, tapped hole depths, drill speeds, bolt circles, countersink depths and sheet metal bend allowance.

Tap Drill Size Calculator (Inch and Metric Threads): The drill to use before tapping a thread, from the standard percentage-of-thread formula, with the nearest number, letter, fractional and metric drills.
Clearance Hole Size Calculator (Close, Normal and Loose Fit): The drill for a bolt or screw to pass through, in close, normal and loose fit, for #0 to 1 in and M1.6 to M30.
Tapped Hole Depth Calculator (Thread Engagement and Drill Depth): How deep to drill and tap a blind hole: thread engagement for steel or aluminium, the tap chamfer, chip room and the drill point.
Drill Speed Calculator (Drill Press RPM for Wood and Metal): Drill press RPM for any drill size in wood, aluminium, brass, cast iron, mild steel and stainless, from the cutting speeds in the US Army machine tool manual.
Bolt Circle Calculator (Hole Coordinates and Spacing): X and Y coordinates of equally spaced holes on a bolt circle, the hole-to-hole spacing and the angle between holes, with a diagram.
Countersink Depth Calculator (82, 90 and 100 Degree): How deep to cut a countersink for a given top diameter and hole size, for 82 degree inch screws, 90 degree metric screws and 100 degree aviation fasteners.
Sheet Metal Bend Allowance Calculator (Setback and Flat Length): Bend allowance, setback, bend deduction and flat pattern length for one bend, with the FAA formula or your own K-factor.

Shop Machines, Turning, Joinery & Shop Business

Lathe speeds, CNC router feed rates, band saw blade lengths, pulley speeds, segmented bowl rings, mortise and tenon sizes, cardboard box templates and what to charge for your work.

Wood Lathe Speed Calculator (Safe RPM by Diameter): A safe starting and maximum lathe RPM for a bowl blank or spindle of any diameter, from the 6,000 to 9,000 rule.
Segmented Bowl Ring Calculator (Miter Angle and Segment Length): Miter angle, segment length and width, and the strip length to cut for one ring of a segmented bowl or vase.
Mortise and Tenon Calculator (Rule of Thirds Sizes): Tenon thickness, width and length and the mortise size and depth for a rail joining a leg or stile, from the rule of thirds.
Woodworking Pricing Calculator (What to Charge for a Project): A selling price for a handmade piece from materials, labor, shop costs, other expenses, profit and marketplace fees.
Cardboard Box Template Calculator (Flat Blank Size and Scores): The flat sheet size, fold lines and flap size to make a standard slotted cardboard box to your inside dimensions.
CNC Router Feed Rate Calculator (Chip Load, RPM and Feed): Feed rate from spindle speed, flutes and chip load, or the chip load you are actually cutting at, for CNC routers in wood and plastics.
Bandsaw Blade Length Calculator (From Wheel Size and Centres): The blade length a band saw needs from its wheel diameters and the distance between wheel centres, with the range the tension adjustment covers.
Pulley Speed Calculator (RPM, Pulley Size and Belt Length): Driven RPM from two pulley sizes, or the pulley size for a target speed, plus belt length and belt speed for shop machines.

How these calculators are checked

All the calculators run on one small calculation engine with 120 automated tests. Where a source publishes a figure, the test uses it: NCMA’s 119 blocks per 100 sq ft, BIA’s 675 modular brick per 100 sq ft, the IRC deck span tables, the AWC DCA 6 footing sizes, USG’s joint compound coverage, Titebond’s 250 sq ft per gallon, the Wood Handbook shrinkage equation and the manufacturer’s concrete bag yields. The build that publishes these pages refuses to run if any test fails. Each page shows the date it was last reviewed. More detail: how we build and check our calculators.

Last reviewed: 26 September 2026. Something wrong or missing? Please get in touch.