CONSTRUCTION · LUMBER

Board Feet Calculator

Calculate the board footage of lumber for your woodworking or construction project. Enter dimensions and quantity to estimate volume and cost.

LAST REVIEWED · APR 24, 2026 · BY D. MARQUEZ, P.E.
You need
80.00 BF
Lumber DimensionsReset
ThicknessNominal (inches)
in
WidthNominal (inches)
in
LengthIn feet
ft
QuantityNumber of pieces
pcs
Pricing
Price per board footVaries by species
USD
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How the board feet calculator works

A board foot is the standard unit for measuring and pricing hardwood lumber. It represents a piece of wood 1 inch thick × 12 inches wide × 1 foot long — or 144 cubic inches. The formula is simple: thickness × width × length ÷ 12.

Common lumber dimensions in board feet

  • 2×4×8 = 5.33 BF
  • 2×6×8 = 8 BF
  • 2×8×12 = 16 BF
  • 1×12×10 = 10 BF

Nominal vs. actual dimensions

Softwood lumber is sold by nominal size (a "2×4" is actually 1.5" × 3.5"). Board feet are calculated using nominal dimensions for softwood and actual rough dimensions for hardwood. This calculator uses the dimensions you enter, so use nominal sizes for framing lumber.

Methodology. Board Feet = Thickness (inches) × Width (inches) × Length (feet) ÷ 12. One board foot equals a piece of lumber 1 inch thick, 12 inches wide, and 1 foot long (144 cubic inches).

Sources

  • National Hardwood Lumber Association (NHLA) grading rules
  • USDA Forest Products Laboratory Wood Handbook
  • Average hardwood lumber prices: $4–$12/BF depending on species (2026)
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Frequently asked questions

How do I convert board feet to linear feet? +
Divide board feet by the cross-section in board feet per linear foot. For a 2×6: each linear foot = 2×6÷12 = 1 BF. So 100 BF of 2×6 = 100 linear feet.
Why do lumberyards price by board foot? +
Board footage normalizes pricing across different dimensions. A thick, wide board uses more wood than a thin, narrow one — board feet account for this so you can compare prices fairly regardless of size.
Should I use nominal or actual dimensions? +
For framing lumber (softwood), use nominal dimensions — that's how it's sold. For hardwood, use the actual rough thickness. Hardwood is typically sold in quarter increments: 4/4 (1"), 5/4 (1.25"), 6/4 (1.5"), 8/4 (2").
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