Board Feet Calculator – Calculate Lumber Board Footage (2026)
Instantly calculate board feet for lumber or logs. Supports multiple pieces, cost estimation by wood species, log scaling (Doyle, Scribner, International), and board feet to linear feet conversion.
Example: 1" thick × 6" wide × 8' long = (1 × 6 × 8) ÷ 12 = 4 board feet
Common lumber dimensions with board footage per linear foot and 2026 average prices by species.
| Nominal Size | Actual Size | BF per Linear Foot | Avg Price/BF (2026) | Common Use | Type |
|---|---|---|---|---|---|
| 2×4 | 1.5" × 3.5" | 1.00 BF | $1.20–$2.00 | Wall framing, studs | soft |
| 2×6 | 1.5" × 5.5" | 1.50 BF | $1.50–$2.50 | Framing, decking | soft |
| 2×8 | 1.5" × 7.25" | 2.00 BF | $1.80–$3.00 | Floor joists, rafters | soft |
| 2×10 | 1.5" × 9.25" | 2.50 BF | $2.00–$3.50 | Headers, beams | soft |
| 2×12 | 1.5" × 11.25" | 3.00 BF | $2.50–$4.00 | Structural beams | soft |
| 1×4 | 0.75" × 3.5" | 0.33 BF | $1.50–$2.50 | Trim, shelving | soft |
| 1×6 | 0.75" × 5.5" | 0.50 BF | $1.80–$3.00 | Siding, shelving | soft |
| 1×12 | 0.75" × 11.25" | 1.00 BF | $2.50–$4.50 | Shelving, cabinets | soft |
| 4×4 | 3.5" × 3.5" | 4.00 BF | $2.00–$3.50 | Posts, fencing | soft |
| White Oak 4/4 | ~1" thick | ~1.00 BF | $4–$8 | Flooring, furniture | hard |
| Cherry 4/4 | ~1" thick | ~1.00 BF | $7–$12 | Cabinets, furniture | hard |
| Walnut 4/4 | ~1" thick | ~1.00 BF | $8–$15 | Fine furniture, turning | hard |
| Teak | ~1" thick | ~1.00 BF | $20–$40 | Marine, outdoor furniture | exotic |
| Purple Heart | ~1" thick | ~1.00 BF | $15–$30 | Decorative, furniture | exotic |
✱ Prices are 2026 US market estimates. Actual prices vary by region, supplier, and lumber grade. Nominal sizes differ from actual (dressed) sizes due to milling.
The Board Feet Formula
Board feet measure lumber volume. The formula is: BF = (Thickness" × Width" × Length') ÷ 12. Example: A board 1.5" thick, 6" wide, and 10' long = (1.5 × 6 × 10) ÷ 12 = 7.5 board feet.
If Length Is in Inches
When all three measurements are in inches, divide by 144 instead: BF = (T" × W" × L") ÷ 144. Example: 1" × 6" × 96" = (1 × 6 × 96) ÷ 144 = 4 board feet.
Adding Waste Factor
For construction framing, add 10–15% waste. For finish carpentry or hardwood projects, add 15–20%. Multiply your net board feet by (1 + waste%) to get the total purchase quantity.
Calculating Board Feet for a Log (Doyle Scale)
For raw logs, use the Doyle formula: BF = ((D − 4) ÷ 4)² × L where D = small-end diameter in inches and L = length in feet. For a 16" × 12' log: ((16−4)÷4)² × 12 = 9 × 12 = 108 board feet.
Use the formula: BF = (Thickness in inches × Width in inches × Length in feet) ÷ 12. For example, a board 1" thick × 6" wide × 8' long = (1 × 6 × 8) ÷ 12 = 4 board feet. For multiple boards, multiply by quantity then add a 10–15% waste factor.
Measure the thickness and width in inches and the length in feet. Apply the formula: BF = (T × W × L) ÷ 12. For dimensional lumber like a 2×4, use actual dimensions (1.5" × 3.5") not nominal for the most accurate result.
Using nominal dimensions: (2 × 4 × 8) ÷ 12 = 5.33 board feet. Using actual dimensions (1.5" × 3.5" × 8'): (1.5 × 3.5 × 8) ÷ 12 = 3.5 board feet. Lumber yards typically sell by nominal size but actual BF content is based on actual dimensions.
The most common method is the Doyle Scale: BF = ((D − 4) ÷ 4)² × L. For a 20" diameter, 16-foot log: ((20−4)÷4)² × 16 = 16 × 16 = 256 BF. The Scribner and International 1/4" scales give slightly different results and are used in different regions.
Linear Feet = (Board Feet × 12) ÷ (Thickness" × Width"). Example: 20 BF of 1×6 lumber = (20 × 12) ÷ (1 × 6) = 40 linear feet. Use the BF → Linear Ft tab in our calculator above.
A board foot measures volume (1" × 12" × 12" = 144 cubic inches). A linear foot measures only length, regardless of cross-section. Hardwoods are sold by the board foot; trim and molding are typically sold by the linear foot.
Softwood (pine, SPF framing lumber) costs approximately $1–$3 per BF. Domestic hardwoods range from poplar ($2–$4) and white oak ($4–$8) to walnut ($8–$15). Exotic species like teak or purple heart can run $20–$40+ per BF depending on grade and supplier.