Will it sag, split, or stick? Check before you cut.
The classic workshop calculators — shelf deflection, seasonal wood movement, equilibrium moisture, board feet, graduated drawers — rebuilt for your phone, fraction-native, with every species value traced to the USDA Wood Handbook and printed next to the answer.
Free, unlimited, no signup — the way workshop calculators should be.
Will it sag? Deflection for any shelf — species, span, load, edging — against the 0.02 in/ft visibility standard.
Free calculatorHow much a board or panel grows and shrinks between seasons, by species and cut, in inches and fractions.
Free calculatorThe equilibrium moisture content your wood is heading for, from temperature and humidity.
Free calculatorA full bill of materials: board feet per part, waste factor, and cost at your local price.
Free calculatorThe bare tally: boards in, total board feet out. Lumber-yard math without the parts list.
Free calculatorGraduated drawer fronts that actually graduate — the traditional geometric progression, solved.
Free calculatorRank all 50 species by what you care about: stiffness, stability, hardness, weight.
Free calculatorScore ten finishes against durability, water, effort and repairability — weighted your way.
The free calculators each answer one question about one part. The Design-Checked Project Kit takes a whole project — bookcase, cabinet, table, dresser, workbench — and checks every shelf and every wide panel at once, with the fix attached to every flag.
Every shelf rated PASS / WATCH / FAIL against the published 0.02 in/ft visibility standard — and when one fails, the kit re-computes the fix: thicker stock, fixed ends, an edging strip, a stiffer species.
Included in the $39 Design-Checked Project Kit
Every wide top, door and drawer front gets its seasonal movement in fractions, plus the clearance to build in — so drawers don't stick in August and tops don't split in January.
Included in the $39 Design-Checked Project Kit
Board feet and cost for the whole project at your local prices, with a one-click species swap: same bookcase in red oak vs poplar vs Baltic birch, verdicts and dollars side by side.
Included in the $39 Design-Checked Project Kit
Projects save in your browser (no account). Print one pack: check summary, validated parts list, and the shopping list by material.
$39 one-time
Get the Design-Check KitParts lists yes, cut layouts no. Checking yes, drawing no.
Every species page carries the full data row — stiffness, shrinkage, hardness, weight — with a sag and movement calculator for that wood built in.