Tools in This Collection
Board Foot Calculator
Convert lumber dimensions to board feet and calculate total cost
Cutting List Optimizer
Arrange parts on standard lumber lengths to minimize waste
Miter Angle Calculator
Calculate miter and bevel angles for polygons and compound cuts
Dovetail Calculator
Lay out evenly spaced pins and tails with adjustable ratio
Box Joint Calculator
Calculate evenly spaced finger joints for a target finger width
Shelf Sag Calculator
Estimate midpoint deflection for shelves under load
Wood Movement Calculator
Estimate seasonal expansion by species, cut, and moisture change
Wood Glue Calculator
Estimate glue volume needed for a joint by surface area
Wood Finish Calculator
Estimate finish quantity by surface area, coats, and finish type
Woodworking Project Planning Workflow
Small errors in woodworking compound into large problems. A half-degree angle error creates a visible gap; a missed board foot calculation leaves you short mid-project; a shelf that doesn't account for load will sag. These calculators give you the accurate numbers that prevent those problems before they happen.
Material Planning and Lumber
The Board Foot Calculator converts lumber dimensions to board feet and total cost. Board feet = (thickness × width × length) ÷ 144 — all in inches. A 1-inch thick × 6-inch wide × 96-inch long board equals 4 board feet. Hardwood dealers price by actual dimensions, so this calculation is essential before pricing a project. The Cutting List Optimizer arranges your part list on standard lumber lengths (8, 10, 12 ft) to minimize waste — showing how many full boards to buy and where to make cuts.
Joinery and Angles
Polygon miter angles follow a simple formula: 360 ÷ (2 × sides) = miter angle. An octagon picture frame requires 22.5° miters. A hexagon requires 30° miters. The Miter Angle Calculator solves both simple polygon miters and compound angles for crown molding and tapered legs. The Dovetail Calculator lays out evenly spaced pins and tails for a given board width with adjustable ratio — 1:8 (7°) for softwoods, 1:6 (9.5°) for hardwoods. The Box Joint Calculator divides a board width into evenly spaced fingers for a target finger width.
Structural Analysis and Finishing
The Shelf Sag Calculator estimates midpoint deflection for any shelf span, thickness, and load using the material's modulus of elasticity. Acceptable deflection is typically L/360 (span divided by 360). The Wood Movement Calculator estimates seasonal expansion per inch of width — flat-sawn hardwoods expand 3-5% across the grain seasonally. The Wood Glue Calculator estimates glue volume for a joint area at standard coverage rates. The Wood Finish Calculator estimates finish quantity (oil, varnish, stain) based on surface area and number of coats.
Frequently Asked Questions
How do I calculate board feet for a lumber purchase?
Board feet = (thickness in inches × width in inches × length in inches) ÷ 144. A 4/4 (1" nominal) board 5" wide and 8' long = (1 × 5 × 96) ÷ 144 = 3.33 board feet. Add 20-30% for waste, defects, and jointing. The Board Foot Calculator handles multiple boards simultaneously and includes waste factor options.
How much does wood move seasonally?
Seasonal movement depends on species, grain orientation, and regional humidity swing. Flat-sawn (plain-sawn) lumber moves most — approximately 1% across the grain per 4% moisture content change. For a typical 8% seasonal swing, expect flat-sawn white oak to expand about 2% of its width. A 12" wide panel could move nearly 1/4 inch. Quartersawn lumber moves roughly half as much. The Wood Movement Calculator computes this for your specific species and conditions.
What miter angle do I need for an octagon frame?
An octagon has 8 sides. The formula is 360 ÷ (2 × 8) = 22.5 degrees. Set your miter saw to 22.5° for all cuts. For a hexagon: 360 ÷ (2 × 6) = 30°. For a pentagon: 360 ÷ (2 × 5) = 36°. The Miter Angle Calculator handles all regular polygons and also solves compound angles for crown molding and tapered workpieces where you need both miter and bevel settings.
When does a shelf need a center support?
A rule of thumb: deflection should not exceed L/360 of the span (span divided by 360). For a 36" pine shelf with 50 lbs of books, expected deflection might be 1/8" — which is 36/360 = 0.1", so you're borderline. The Shelf Sag Calculator computes exact deflection for your material, span, thickness, and load — helping you decide whether to use a thicker shelf, a stiffer species, or add center support.