How this board foot calculator works
A board foot is lumber's volume unit — 144 cubic inches of nominal wood. One formula, no exceptions:
The calculator multiplies one board out, scales by the count, and prices the tally at your rate per board foot (with the MBF equivalent for wholesale quotes). At the defaults — ten 1 × 6 × 8 ft boards — that’s 40 BF and $200; the math is in the tally section below.
Nominal, actual, and quarters
The board foot trips people up because it measures a board that no longer exists by the time you hold it. Three ideas clear it up:
Nominal size
The rough-sawn dimension the mill cut before surfacing — the “2×4” on the tag. Board feet are always figured on nominal, so a 2×4 counts as a full 2 × 4 even though it planes down.
Actual size
What the surfaced board really measures — a 2×4 is 1½ × 3½, a 1× is ¾ thick. You design and fit to actual, but you buy and tally by nominal. The gap is the sawdust and shavings the planer took.
Quarters (hardwood thickness)
Hardwood is sold in quarter-inch thicknesses: 4/4 (“four-quarter”) is 1 in nominal, 5/4 is 1¼, 6/4 is 1½, 8/4 is 2. The chips on the calculator set them directly, so a rough 4/4 board tallies at its full nominal inch.
What a board foot of lumber costs
Board feet are the currency of hardwood and rough stock — softwood framing usually prices per piece or per linear foot instead. Where the 2026 market roughly sits, per board foot:
| Species | Typical range |
|---|---|
| Poplar | $3–5 |
| Red / white oak | $4–7 |
| Hard maple | $5–8 |
| Cherry | $6–10 |
| Walnut | $10–16 |
| Figured / exotic | $15+ |
Grade matters as much as species: FAS and Select run well above Common grades of the same wood, and wider boards carry a premium per foot. A “$5 oak” number is a starting point, not a quote.
Board feet in common lumber sizes
Table 2 lists board feet per 8 ft board for the everyday sizes — scale linearly for other lengths (a 2×4×10 is 6.67 BF, a 2×4×12 is 8).
| Nominal size | Board feet |
|---|---|
| 1 × 6 | 4 |
| 1 × 8 | 5.33 |
| 2 × 4 | 5.33 |
| 2 × 6 | 8 |
| 2 × 8 | 10.67 |
| 2 × 10 | 13.33 |
| 2 × 12 | 16 |
How to tally board feet
Whether you’re pricing a furniture project or a rough-lumber order, the tally is the same few moves:
- Use nominal dimensions. Thickness and width in inches, length in feet — the tag size, not the planed size.
- Set the count for identical boards; the calculator multiplies per-board BF by it.
- Group a mixed pile by size. Run each size as its own stack and add the totals — board feet sum straight across.
- Add a cutting allowance for hardwood projects — 15–30% over the finished BF, because rough boards have waney edges and defects you’ll cut around.
- Enter your $/BF or convert an MBF quote ($800/MBF = $0.80/BF) — the calculator shows both so wholesale and retail line up.
Worked example: a stack of 4/4 stock
The default, worked line by line — ten 4/4 × 6 in × 8 ft boards at $5 per board foot:
stack = 4 × 10 = 40 BF
cost = 40 × $5 = $200
as MBF = 40 ÷ 1,000 = 0.04 MBF
A hardwood dealer will tally your cart exactly this way — nominal thickness in quarters, nominal width in inches, length in feet, all over 12. The one thing the tally doesn’t add is cutting waste: buy 40 finished board feet of rough walnut and you’ll want closer to 50 on the truck.
What the board-foot tally doesn’t tell you
- Cutting waste. Rough boards yield less usable wood than their board feet — add 15–30% for a furniture cut list.
- Grade and defects. Board feet count knots and sapwood the same as clear wood; the grade sets what’s usable.
- Actual thickness. Design and joinery work off the surfaced size, not the nominal the tally uses.
- Softwood pricing. Framing lumber usually sells per piece or per linear foot — board feet are mainly a hardwood and rough-stock unit.
- Moisture. Green versus kiln-dried changes both price and how the board behaves — a separate question from volume.
Board foot FAQ
What is a board foot?
A volume unit for lumber: 144 cubic inches, the size of a 1 in × 12 in × 12 in piece — figured on nominal (rough-sawn) dimensions. Board feet = thickness (in) × width (in) × length (ft) ÷ 12.
How many board feet are in a 2×4×8?
5.33 board feet: 2 × 4 × 8 ÷ 12. A 2×6×8 is 8 BF, a 2×10×8 is 13.33, and a 2×12×8 is 16 — the table on this page lists the common sizes.
How do you calculate board feet for a whole project?
Tally each board as thickness × width × length ÷ 12, then add them up — or group by size and multiply by the count, which is what the count field here does. For a mixed pile, run each size as its own stack and sum the board-foot totals; the price follows at your $/BF.
Why do board feet use nominal sizes when the wood is smaller?
Because the measure describes the rough-sawn board the mill started from, before surfacing takes it to 1½ × 3½. Hardwood dealers price the same way in "quarters" — 4/4 is 1 in nominal, 8/4 is 2 in — so nominal-in, nominal-out is the trade convention everywhere.
What is the difference between a board foot and a linear foot?
A linear foot is just length along the board, ignoring section; a board foot is volume. Dimensional framing lumber usually prices per piece or per linear foot, while hardwoods and rough stock price per board foot — this calculator converts your tally for the latter.
What is MBF?
A thousand board feet — the unit mills and wholesalers quote in ("M" is the Roman thousand). $800 per MBF is $0.80 per board foot. The calculator shows the MBF equivalent of your tally so a wholesale quote and a retail one line up.
How much does a board foot of lumber cost?
In 2026, roughly $3–6 per board foot for common domestic hardwoods like oak, maple and ash, $6–12 for walnut and cherry, and more for figured or exotic stock. Type your quote into the price field — dealers also quote per MBF (thousand board feet) for volume.
Sources and standards
- NHLA rules: the National Hardwood Lumber Association grading and board-foot tallying conventions this calculator follows.
- Quarter (4/4) thickness system: the hardwood-trade nominal thicknesses behind the thickness chips.
- The board-foot definition: 144 cubic inches — thickness × width × length ÷ 12 on nominal dimensions, computed, not estimated.
- MBF convention: the thousand-board-foot wholesale unit the price line converts to.
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