A workshop reference, built on USDA data
Wood calculators & species data
Free woodworking calculators & reference charts — every value traceable to the USDA Wood Handbook.
Calculators & charts
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Board Foot Calculator
Convert thickness × width × length into board feet, with quarter sizes (4/4–12/4) and cost per board foot.
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Wood Movement Calculator
Predict how much a board will expand or shrink across the grain for a given species, width, and humidity swing.
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Janka Hardness Chart
Sortable hardness chart in pounds-force — see which woods resist dents and wear, and what the test really measures.
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Wood Weight Calculator
Estimate lumber weight from species and dimensions using 12% MC densities.
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Wood Density Chart
Density in lb/ft³ and kg/m³ with specific gravity, plus weight per board foot for quick estimates.
Species data cards
Per-species shrinkage, movement tables, hardness, density, weight, and seasonal city-by-city movement — one page per wood (59 at launch, drawn from a 196-species dataset that also powers the Janka and density charts):
- African Ebony
- African Mahogany
- Afrormosia
- American Beech
- American Chestnut
- American Sycamore
- Apitong
- Balsa
- Black Ash
- Black Cherry
- Black Locust
- Black Oak
- Black Walnut
- Bubinga
- Bur Oak
- Butternut
- Coast Douglas-fir
- Cocobolo
- Eastern Redcedar
- Eastern White Pine
- Greenheart
- Hackberry
- Honeylocust
- Imbuia
- Indian Rosewood
- Ipe
- Iroko
- Jarrah
- Live Oak
- Merbau
- Northern Red Oak
- Obeche
- Okoume
- Old Growth Redwood
- Pacific Madrone
- Pecan Hickory
- Ponderosa Pine
- Post Oak
- Purpleheart
- Red Alder
- Red Maple
- Red Pine
- Rubberwood
- Sapele
- Sassafras
- Shagbark Hickory
- Silver Maple
- Sitka Spruce
- Spanish-cedar
- Sugar Maple
- Sweetgum
- Tamarack
- Teak
- True Mahogany
- Western Redcedar
- White Ash
- White Oak
- Yellow Birch
- Yellow-poplar
Data: USDA Forest Products Laboratory, Wood Handbook FPL-GTR-282 (2021), public domain.
What this site is
TimberMath is a free set of woodworking calculators and reference tables built on public U.S. government data (USDA Forest Products Laboratory Wood Handbook, FPL-GTR-282, 2021). Use it to convert lumber to board feet, predict seasonal wood movement by species, compare Janka hardness, and look up density, shrinkage, and weight for 196 North American and imported woods.
TimberMath is an independent data project. The numbers behind every tool come from the USDA Forest Products Laboratory's Wood Handbook (FPL-GTR-282, 2021) — the standard public-domain reference for wood properties — and every calculator documents its formula on the page, so you can check the math yourself. Read more on the methodology page.