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Free woodworking calculators

Calculators and reference charts for shelf sag, lathe speeds, segmented turning, cutting boards, and more. No ads, no logins.

Design your own

Cutting Board DesignerCompose a board strip by strip — live 3D, drawing views, and an exact cut list.Templates8 patterns with cut lists — open any of them in the designer.GalleryShare your build. The gallery is just getting started.GuidesLong-form build guides that put the calculators to work.

Shelving & Structure1 tool

Shelf Sag CalculatorFeaturedWill your shelf hold books without bowing? Deflection by species, span, thickness, and load — with a long-term creep estimate.

Woodturning2 tools

Wood Lathe Speed CalculatorSafe RPM by blank diameter — roughing to sanding, with unbalanced-blank guidance and rim speed shown.Segmented Turning CalculatorMiter angle, segment lengths, and strip length for any ring — with a live diagram of your segment count.

Boards & Panels6 tools

Board Foot CalculatorFeaturedThickness × width × length to board feet, with 4/4–8/4 presets, piece counts, cost — and a live 3D board preview.Wood Movement CalculatorSeasonal expansion and shrinkage by species, grain orientation, and moisture swing — FPL data, gap guidance included.Epoxy Pour CalculatorRiver-table and mold volume in ounces and liters, with waste allowance, A/B mix split, and a deep-pour depth check.End Grain Cutting Board CalculatorStrips to rip, slices to cut, and board feet to buy — with a live checkerboard preview of your pattern.Kerf Bending CalculatorKerf count, spacing, and cut depth for any bend — real geometry, live diagram.Plywood Cut List OptimizerFeaturedPack your parts onto 4×8 or 5×5 sheets — kerf and grain direction handled, with sheet count, waste %, and a to-scale cutting diagram per sheet.

Shop Reference6 tools

Wood Weight CalculatorSpecies density × your dimensions = pounds and kilograms, with board feet alongside and a 3D preview to scale.Bandsaw Blade Length CalculatorWheel sizes and center distance in, blade length out — with ordering advice.Wood Screw Pilot Hole ChartPilot, clearance, and hardwood/softwood sizes by screw gauge — fractional or metric.Firewood Cord CalculatorStack size to cords, with an effective price-per-cord check for buying season.Router Bit Speed ChartEnter a bit diameter, get the safe max RPM — with the full reference table.Janka Hardness ChartFeaturedSortable, searchable hardness ratings for 55+ species, in lbf or newtons.

Carpentry & Trim3 tools

Crown Molding Angle CalculatorSpring angle + your actual corner = miter and bevel for cutting crown flat.Compound Miter CalculatorSides and slope in — miter and bevel angles out, in degrees from square, with the miter-gauge setting for sloped-side boxes and frames.Stair Stringer CalculatorTotal rise to full layout: risers, treads, run, stringer length, comfort check.

Built like a good jig

Each tool page shows how its numbers are worked out, and a Checks line under the title says what has and has not been verified for that tool. Where a number matters for safety, the page says so. Found an error? Tell us.