Board Foot Calculator
Calculate board feet for a single board or a full lumber order, and total the cost at your price per board foot. Uses the standard nominal-dimension formula sawmills and hardwood dealers use.
4/4 = 1″ · 6/4 = 1.5″ · 8/4 = 2″
Typical: pine $2–4 · oak $5–8 · walnut $10–15 per bd ft
You might also need:Stair Calculator·Rafter Calculator
The board foot formula
or: (thickness in × width in × length in) ÷ 144
One board foot is a 12 × 12 × 1 inch slab of wood. Because it measures volume, a thick short board can contain more wood than a long thin one — which is why hardwood is priced this way rather than by length.
Board feet in common lumber sizes
| Nominal size | 8 ft | 10 ft | 12 ft | 16 ft |
|---|---|---|---|---|
| 1×6 | 4 | 5 | 6 | 8 |
| 1×8 | 5.3 | 6.7 | 8 | 10.7 |
| 2×4 | 5.3 | 6.7 | 8 | 10.7 |
| 2×6 | 8 | 10 | 12 | 16 |
| 2×8 | 10.7 | 13.3 | 16 | 21.3 |
| 2×10 | 13.3 | 16.7 | 20 | 26.7 |
| 2×12 | 16 | 20 | 24 | 32 |
Buying hardwood without surprises
- Nominal vs actual: you pay for rough-sawn volume. A surfaced 4/4 board at 13/16″ thick still bills as 1″.
- Random widths are normal: hardwood comes in whatever widths the log gave. Tally each board's actual bd ft — dealers round to the nearest quarter or half foot.
- Add waste before you shop: 15–20% extra covers defects and grain matching. Running stair stringers or framing instead? Our stair calculator works out the lumber lengths you need.
Frequently asked questions
What is a board foot?+
A board foot is a volume measure of lumber equal to 144 cubic inches — a piece 12 inches × 12 inches × 1 inch thick. Hardwood is priced per board foot; construction softwood is usually priced per piece instead.
How do I calculate board feet?+
Multiply thickness (inches) × width (inches) × length (feet), then divide by 12. An 8-foot 2×6 is 2 × 6 × 8 ÷ 12 = 8 board feet.
Do I use nominal or actual dimensions for board feet?+
Board feet are traditionally calculated on nominal (rough-sawn) dimensions — a 2×6 counts as 2 by 6 inches even though it measures 1½ × 5½ after surfacing. Hardwood dealers use quarter thickness (4/4, 8/4) which is also the rough size.
What does 4/4, 6/4 and 8/4 lumber mean?+
Hardwood thickness is quoted in quarters of an inch of rough thickness: 4/4 ("four-quarter") is 1 inch, 6/4 is 1½ inches, 8/4 is 2 inches. After surfacing, 4/4 typically finishes at 13/16 inch.
How much waste should I add to a lumber order?+
Add 15–20% for hardwood projects to allow for defects, checking, and grain matching — more for character-grade boards. For construction framing, 10% covers offcuts and culls.