Saisissez les dimensions — les résultats se mettent à jour instantanément. Formule : BF = (T in × W in × L ft) ÷ 12.
Saisissez les dimensions — les résultats se mettent à jour instantanément. Formule : BF = (T in × W in × L ft) ÷ 12.
Un board foot est un volume de bois égal à 144 pouces cubes. On peut aussi le voir comme 1 ft² de surface sur 1 pouce d’épaisseur, ou 1/12 de pied cube.
Comme la plupart des bois sont vendus en tailles « 1×, 2× » mais rabotés à des dimensions réelles légèrement plus petites, de nombreux calculs utilisent l’épaisseur et la largeur réelles.
Un 2×4 nominal mesure en réalité env. 1.5 in × 3.5 in après séchage et rabotage. Pour estimer le BF, les tailles réelles donnent des totaux plus réalistes. Les préréglages de l’outil remplissent des tailles rabotées typiques.
Utile pour estimer de longues longueurs (BF/ft = T × W ÷ 12).
| Taille (réelle) | BF par pied |
|---|---|
| 1×4 (0.75″ × 3.5″) | — |
| 1×6 (0.75″ × 5.5″) | — |
| 1×8 (0.75″ × 7.25″) | — |
| 2×4 (1.5″ × 3.5″) | — |
| 2×6 (1.5″ × 5.5″) | — |
| 2×8 (1.5″ × 7.25″) | — |
| 2×10 (1.5″ × 9.25″) | — |
| 2×12 (1.5″ × 11.25″) | — |
Calculate board feet in real-time as you type dimensions
Uses standard BF = (T × W × L) ÷ 12 calculation
Get instant price estimates for your lumber needs
Un board foot (BF) est une mesure de volume pour le bois égale à 144 in³ (12 in × 12 in × 1 in). Le calculateur utilise la formule standard :
Les valeurs se mettent à jour à mesure que vous saisissez. Utilisez les préréglages pour les tailles rabotées courantes (ex. : 2×4 réel 1.5 in × 3.5 in).
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Understanding the mathematical foundation behind board foot calculations
BF = (T × W × L) ÷ 12
T = Thickness in inches
W = Width in inches
L = Length in feet
BF = Board Feet
One board foot equals 144 cubic inches (12″ × 12″ × 1″). When we multiply thickness (inches) × width (inches) × length (feet), we get a result in "inch²-feet". Dividing by 12 converts this to board feet, the standard unit for lumber volume.
Start with dimensions
2×4 board, 8 feet long
Actual: 1.5″ thick × 3.5″ wide × 8′ long
Multiply dimensions
1.5 × 3.5 × 8 = 42
Divide by 12
42 ÷ 12 = 3.5 BF
Result: 3.5 Board Feet
Common lumber calculations you'll encounter in projects
Material: 5/4 × 6 decking
Actual Size: 1″ × 5.5″
Length: 12 feet
Quantity: 50 boards
(1 × 5.5 × 12) ÷ 12 = 5.5 BF
Total: 275 BF
Material: 2×4 studs
Actual Size: 1.5″ × 3.5″
Length: 8 feet
Quantity: 100 studs
(1.5 × 3.5 × 8) ÷ 12 = 3.5 BF
Total: 350 BF
Material: 8/4 oak
Actual Size: 2″ × 8″
Length: 6 feet
Quantity: 8 boards
(2 × 8 × 6) ÷ 12 = 8 BF
Total: 64 BF
Quick reference for common lumber sizes and their board foot values per linear foot
| Nominal Size | Actual Size | BF per Foot | BF per 8' | BF per 10' | BF per 12' |
|---|---|---|---|---|---|
| 1×4 | 0.75″ × 3.5″ | 0.219 | 1.75 | 2.19 | 2.63 |
| 1×6 | 0.75″ × 5.5″ | 0.344 | 2.75 | 3.44 | 4.13 |
| 1×8 | 0.75″ × 7.25″ | 0.453 | 3.63 | 4.53 | 5.44 |
| 2×4 | 1.5″ × 3.5″ | 0.438 | 3.50 | 4.38 | 5.25 |
| 2×6 | 1.5″ × 5.5″ | 0.688 | 5.50 | 6.88 | 8.25 |
| 2×8 | 1.5″ × 7.25″ | 0.906 | 7.25 | 9.06 | 10.88 |
| 2×10 | 1.5″ × 9.25″ | 1.156 | 9.25 | 11.56 | 13.88 |
| 2×12 | 1.5″ × 11.25″ | 1.406 | 11.25 | 14.06 | 16.88 |
Note: Values are based on actual (dressed) dimensions, not nominal sizes. Actual dimensions are slightly smaller due to planing and drying. Use these values for accurate material estimates.
Master the art of calculating board feet with our comprehensive guide
Most common method for lumber:
Example: (1.5 × 5.5 × 10) ÷ 12 = 6.875 BF Alternative method using inches:
Example: (1.5 × 5.5 × 120) ÷ 144 = 6.875 BF Quick calculation for long runs:
Example: (1.5 × 5.5) ÷ 12 = 0.6875 BF/ft
0.6875 × 10 ft = 6.875 BF