Lumber Calculator
Calculate board feet, total lumber needed, and cost estimate for your woodworking or construction project.
Quick Answer
Board feet = (Thickness" × Width" × Length') / 12. One board foot is a piece 1" thick, 12" wide, and 1' long. A standard 2x4x8 contains 5.33 board feet. Hardwood is priced per board foot ($3-$15+) while construction lumber is typically priced per piece.
Results
Common Lumber Sizes Reference
| Nominal | Actual | BF per 8' |
|---|---|---|
| 1 x 4 | 3/4" x 3-1/2" | 1.75 |
| 1 x 6 | 3/4" x 5-1/2" | 2.75 |
| 1 x 8 | 3/4" x 7-1/4" | 3.63 |
| 2 x 4 | 1-1/2" x 3-1/2" | 3.50 |
| 2 x 6 | 1-1/2" x 5-1/2" | 5.50 |
| 2 x 8 | 1-1/2" x 7-1/4" | 7.25 |
| 2 x 10 | 1-1/2" x 9-1/4" | 9.25 |
| 2 x 12 | 1-1/2" x 11-1/4" | 11.25 |
| 4 x 4 | 3-1/2" x 3-1/2" | 8.17 |
About This Tool
The board foot is the standard unit of measurement for hardwood lumber in North America. Understanding board feet is essential for pricing hardwood at lumber yards, estimating project costs, and comparing prices between suppliers. This calculator handles the math so you can focus on your project design and material selection.
Board Foot Formula
The formula is straightforward: Board Feet = (Thickness in inches × Width in inches × Length in feet) / 12. This gives you the volume equivalent of a board that is 1 inch thick, 12 inches wide, and 1 foot long. When buying hardwood, remember that thickness is typically expressed in "quarters": 4/4 means 1 inch thick (actually about 13/16" after surfacing), 5/4 is 1.25 inches, 6/4 is 1.5 inches, and 8/4 is 2 inches.
Nominal vs. Actual Dimensions
Construction lumber (pine, fir, SPF) uses nominal sizing where a "2x4" actually measures 1.5" x 3.5". This is because lumber is sized before drying and planing, which removes about 1/2" from each dimension. Hardwood lumber is sold rough-sawn at nominal thickness and then surfaced (S2S = surfaced two sides) by the buyer, losing about 3/16" per side. Always calculate board feet using actual dimensions for accuracy.
Lumber Pricing Factors
Softwood construction lumber is typically priced per piece at home centers. Hardwood lumber is priced per board foot, with prices varying dramatically by species: poplar ($3-5/BF), red oak ($5-8/BF), cherry ($6-10/BF), walnut ($8-15/BF), and exotic species ($12-30+/BF). Prices also depend on grade (FAS is highest, #1 Common is mid-grade), thickness, and whether the board is surfaced.
Frequently Asked Questions
What is a board foot?
Why is a 2x4 not actually 2 inches by 4 inches?
How do I calculate board feet for rough lumber?
How much extra lumber should I buy for waste?
What is the cheapest hardwood for woodworking?
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