Board Foot Calculator

Calculate board feet for any lumber dimension. Enter thickness (in), width (in), length (ft), and quantity — get board feet per board, total board feet, and total linear feet.

in

Nominal thickness. Common: 1" (1×4, 1×6), 2" (2×4, 2×6, 2×8), 4" (4×4, 4×6).

in

Nominal width. Common: 4, 6, 8, 10, 12 inches.

ft

Board length in feet. Common: 8, 10, 12, 16 ft.

Number of identical boards. Defaults to 1.

How this calculator works

A board foot (bf) is a volume measurement equal to 144 cubic inches (1 inch × 12 inches × 12 inches, or 1/12 of a cubic foot). It's the standard unit for pricing rough lumber and hardwoods.

The formula is:

board feet = (thickness_in × width_in × length_ft) / 12

For multiple identical boards, multiply by the quantity. The calculator also returns total linear feet (length × quantity), which is the standard unit for pricing softwood framing lumber.

Formula

board_feet_per_board = (thickness_in × width_in × length_ft) / 12
total_board_feet = board_feet_per_board × quantity
total_linear_feet = length_ft × quantity

Example

For a 1×6 board that is 8 ft long (a common deck board size):

  • board_feet = (1 × 6 × 8) / 12 = 48 / 12 = 4 board feet
  • For 10 boards: total = 4 × 10 = 40 board feet
  • Total linear feet = 8 × 10 = 80 linear ft

For a 2×4 that is 8 ft long: (2 × 4 × 8) / 12 = 64/12 ≈ 5.33 board feet per board.

Important assumptions

  • Use nominal dimensions for estimating (e.g. a 2×4 actually measures 1.5×3.5 inches). Most lumber is sold by nominal size, so this matches how yards price boards.
  • For precise volume calculations (e.g. calculating actual wood volume for weight or shipping), use actual dimensions.
  • Hardwood is sold by the board foot. Softwood framing lumber is typically sold by linear foot or per-piece, not by board foot.
  • Quantity defaults to 1 if left blank.
  • This calculator does not account for kerf (saw blade width) or waste — add 10–15% extra when ordering rough lumber.

FAQ

What is a board foot?
A board foot (bf) is a volume measurement equal to 144 cubic inches (1" × 12" × 12"). It's the standard unit for pricing rough lumber and hardwoods.
How do I calculate board feet for a 2×4?
Use nominal dimensions: (2 × 4 × length_in_ft) / 12. An 8-foot 2×4 has (2 × 4 × 8) / 12 = 64/12 ≈ 5.33 board feet.
Should I use nominal or actual dimensions?
Use nominal dimensions (e.g. 2×4, not 1.5×3.5) for estimating and pricing — that's how lumberyards quote prices. Use actual dimensions only if you need exact wood volume (e.g. for weight or shipping calculations).
What's the difference between board feet and linear feet?
A linear foot is just a length measurement (12 inches of board, regardless of thickness or width). A board foot is a volume measurement that accounts for thickness and width. A 2×12 has 2 board feet per linear foot; a 1×4 has 0.33 board feet per linear foot.
Is hardwood sold by board foot or by the piece?
Hardwood lumber is typically sold by the board foot. Softwood framing lumber (2×4, 2×6, etc.) is sold by the piece or by linear foot. Specialty items like trim and molding are sold by linear foot.