Board Foot Calculator
Calculate lumber volume in board feet (BF) from thickness × width × length. Formula: BF = T × W × L / 12 (T and W in inches, L in feet).
Reviewed & updated for 2026 by Rakesh Choudhary, PhD · How we calculate
Common lumber board foot reference
| Nominal size | BF per linear ft | 8 ft board | 16 ft board |
|---|---|---|---|
| 1 × 4 | 0.33 BF/ft | 2.67 BF | 5.33 BF |
| 1 × 6 | 0.50 BF/ft | 4.00 BF | 8.00 BF |
| 1 × 8 | 0.67 BF/ft | 5.33 BF | 10.67 BF |
| 1 × 10 | 0.83 BF/ft | 6.67 BF | 13.33 BF |
| 2 × 4 | 0.67 BF/ft | 5.33 BF | 10.67 BF |
| 2 × 6 | 1.00 BF/ft | 8.00 BF | 16.00 BF |
| 2 × 8 | 1.33 BF/ft | 10.67 BF | 21.33 BF |
| 2 × 10 | 1.67 BF/ft | 13.33 BF | 26.67 BF |
Why hardwood is priced in board feet (and softwood usually isn't)
Walk into a Home Depot and you'll see 2x4s priced per piece. Walk into a hardwood dealer and you'll see a sign reading "Walnut: $14.50/BF." This isn't arbitrary — the two markets have different economic structures, and the unit reflects how each one actually trades.
Softwood (pine, spruce, fir) is mass-produced from fast-growing plantation trees in standardized dimensions. Almost every 2x4 is the same — same length, same species, same grade. So lumberyards sell them by the piece. A 2x4x8 is a commodity SKU.
Hardwood is different. A walnut log is sawn into boards of varying widths and lengths depending on the tree's geometry. A "1x8" walnut board might actually be 7.5 inches wide on one end and 9 inches on the other, and 11 feet 4 inches long. Pricing each piece individually would be a nightmare. Board feet measures the actual volume of wood you walk out with, regardless of which random pieces the saw produced.
This is also why hardwood prices vary so widely. A board foot of pine costs $3 because pine grows fast, ships easily, and is graded mostly on visual appearance. A board foot of walnut costs $14 because the trees take 70+ years to mature, the heartwood is unpredictable, and the best boards command premium prices for furniture and gunstocks.
Estimating board feet for a real project
Calculator output is volume needed. Actual lumber required is always more. Most cabinetmakers and furniture builders add waste between 20 and 40 percent depending on the project. Here's a realistic breakdown for a dining table:
| Component | Finished size | Net BF | With 30% waste |
|---|---|---|---|
| Tabletop (5 boards) | 1" × 8" × 6' | 20.0 | 26.0 |
| Legs (4) | 3" × 3" × 30" | 7.5 | 9.75 |
| Apron rails (4) | 1" × 5" × 5' | 8.33 | 10.83 |
| Breadboard ends (2) | 1" × 4" × 3' | 2.0 | 2.6 |
| Total | — | 37.83 BF | 49.18 BF |
In walnut at $14/BF that's roughly $690 in lumber for the wood alone. In oak it would be $300. Pricing the table at $1,200 retail starts to make sense once you include hardware, finish, and 30+ hours of build time.
Add extra waste on top of the table above if you're: ripping wide stock down to narrower pieces (30% becomes 40%), working with figured grain that has more defects (40% becomes 50%), or buying random-width hardwood where you can't pre-select boards (50%+).
FAQs
What is a board foot?
A board foot is a unit of lumber volume equal to 144 cubic inches (12" × 12" × 1"). It measures hardwood and other dimensional lumber. Formula: Board feet = (Thickness × Width × Length) / 144, where thickness and width are in inches and length is in feet. (Or all in inches, divide by 144.)
How do I calculate board feet?
Use the formula: BF = (T × W × L) / 12, where T = thickness in inches, W = width in inches, L = length in feet. Example: 1" × 8" × 10' board = (1 × 8 × 10) / 12 = 6.67 board feet. For multiple boards, multiply by the number of boards.
What's the difference between board foot and square foot?
Board foot measures VOLUME (with thickness); square foot measures AREA (no thickness). A 2" × 4" × 8' board = 5.33 board feet (volume) but covers 4 sq ft (area) of wall when used flat. Board feet matters for lumber pricing; square feet matters for room coverage.
Why is lumber sold in board feet?
Hardwood lumber prices vary by species AND thickness, so volume (board feet) is the natural unit. Pine and softwoods are sometimes sold by board feet or by 'linear foot' (just length). 1,000 board feet = MBF, the standard wholesale unit.
How much does lumber cost per board foot?
Highly varies by species: Pine: $3-$5/BF. Oak: $4-$8/BF. Maple: $5-$10/BF. Walnut: $10-$18/BF. Cherry: $8-$15/BF. Mahogany: $12-$25/BF. Exotic hardwoods: $20-$50+/BF. Prices vary by grade (FAS, Select, #1 Common) and dimensions. Buy thicker stock for projects requiring resawing.
What's the difference between nominal and actual lumber sizes?
Nominal: the size you ASK for at the lumberyard ('2x4'). Actual: what you ACTUALLY get after kiln-drying and planing ('1.5" × 3.5"'). For board foot calculations, always use NOMINAL dimensions, that's how lumber is sold and priced. 2x4 × 8' is 5.33 BF nominal, regardless of actual dimensions.