Lumber Calculator

Calculate board feet for lumber orders. Enter board thickness, width, length, and quantity to find total board feet, linear feet, and estimated cost. Ideal for woodworking, framing, and construction projects.

Board Feet Calculator

Board Feet Formula

Board Feet = (thickness_in × width_in × length_ft) / 12 Total BF = Board Feet per piece × quantity A "1 board foot" = 1 inch thick × 12 in wide × 12 in long (= 144 cubic inches)

Common Lumber Sizes

Nominal SizeActual SizeBF per 8-ft board
1×40.75" × 3.5"2.67
1×60.75" × 5.5"4.00
1×80.75" × 7.25"5.33
2×41.5" × 3.5"5.33
2×61.5" × 5.5"8.00
2×81.5" × 7.25"10.67

Frequently Asked Questions

What is a board foot?+
A board foot is a unit of volume for lumber equal to 144 cubic inches — the equivalent of a 1-inch thick, 12-inch wide, 12-inch long board. It's the standard unit for pricing hardwood and rough-sawn lumber.
Should I use nominal or actual dimensions?+
For board feet calculations, use nominal dimensions (the stated size like 2×4), not actual dimensions, as that's how lumber is sold and priced. For structural calculations and joinery, use actual dimensions.

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