How to calculate board feet
One formula covers every board:
board feet = thickness″ × width″ × length″ ÷ 144
Let the calculator do the arithmeticEvery part in your project, priced and totaled while you type — free, works offline.
Worked examples
A 4/4 board, 6″ wide, 8′ long. Thickness 1″, width 6″, length 96″: 1 × 6 × 96 ÷ 144 = 4 BF.
Four 8/4 table legs, 3″ × 30″. Each leg is 2 × 3 × 30 ÷ 144 = 1.25 BF; four legs are 5 BF. At $9.50/BF walnut that's $47.50 before waste.
Length in feet? Multiply by 12 first, or use t″ × w″ × ft ÷ 12 — same answer.
Three rules that save money
- Hardwood is billed on rough thickness. Surfaced 4/4 is ~13/16″ thick but costs a full inch. (Details.)
- Buy 15–20% over your math for defects, milling, and mistakes.
- Random widths mean your parts won't nest perfectly — plan parts, not just totals. (The planner exists for exactly this.)
Lookup table — board feet per 4/4 board
For 8/4 double the numbers; for 6/4 multiply by 1.5. Print this page for the shop.
| Width | 4′ | 6′ | 8′ | 10′ | 12′ | 16′ |
|---|---|---|---|---|---|---|
| 2″ | 0.67 | 1.00 | 1.33 | 1.67 | 2.00 | 2.67 |
| 3″ | 1.00 | 1.50 | 2.00 | 2.50 | 3.00 | 4.00 |
| 4″ | 1.33 | 2.00 | 2.67 | 3.33 | 4.00 | 5.33 |
| 6″ | 2.00 | 3.00 | 4.00 | 5.00 | 6.00 | 8.00 |
| 8″ | 2.67 | 4.00 | 5.33 | 6.67 | 8.00 | 10.67 |
| 10″ | 3.33 | 5.00 | 6.67 | 8.33 | 10.00 | 13.33 |
| 12″ | 4.00 | 6.00 | 8.00 | 10.00 | 12.00 | 16.00 |