Board Foot Calculator
Board feet = thickness (in) × width (in) × length (ft) ÷ 12, using the nominal size. One board foot is 144 in³, so a 1x6 has half a board foot per lineal foot. Ten 5/4 × 6 in boards 8 ft long total 50 board feet. For pieces and lineal feet, use the Lumber Calculator.
How it's calculated: Board feet = nominal thickness (in) × nominal width (in) × length (ft) ÷ 12 × pieces.
Result appears here
Fill in the fields and press Calculate.
Formula, calculation, assumptions and sources
Board feet = (Thickness_in × Width_in × Length_in ÷ 144) × pieces
or equivalently (Thickness_in × Width_in × Length_ft ÷ 12) × pieces
Run the calculation to see each step with your own numbers.
Ten pieces of 5/4 × 6 in × 8 ft hardwood.
One piece = (1.25 × 6 × 96) ÷ 144 = 5.0 bd ft
× 10 = 50 board feet
- Uses NOMINAL dimensions (what the board is called), which is how board feet are traded — not the actual surfaced size.
- Length is the full board length; no allowance for defects or trimming.
- Nominal or actual size?
- Nominal. A '1×6' is milled to 3/4 × 5-1/2, but it's sold as 1×6 and its board footage is figured on the 1×6.
- How does board feet relate to lineal feet?
- For a given board, board feet = lineal feet × (nominal thickness × nominal width ÷ 12). A 1×6 has 0.5 bd ft per lineal foot.
- How do you calculate board feet?
- Multiply the nominal thickness and width in inches by the length in feet, divide by 12, then multiply by the number of pieces. A 5/4 × 6 in board 8 ft long is 1.25 × 6 × 8 ÷ 12 = 5 board feet.
- How many board feet are in a 2x4x8?
- 5.33 board feet on its nominal size: 2 × 4 × 8 ÷ 12. Board feet use the nominal dimensions, not the 1½ × 3½ in surfaced size.
Definition
1 board foot = 144 in³ of nominal lumber (National Hardwood Lumber Association). Unit conversions per NIST SP 811.
About the Board Foot Calculator
The Board Foot Calculator turns a piece of lumber — or a stack of identical pieces — into board feet, the volume unit hardwood is priced and sold in. One board foot is 144 cubic inches of nominal lumber, so a 1x6 has half a board foot per lineal foot. It uses the nominal size (what the board is called), not the smaller surfaced size.
What you enter
- Thickness (nominal) — Nominal, in inches — a 5/4 board is 1.25.
- Width (nominal)
- Length
- Number of pieces
What you get back
- Board feet — Hardwood is priced per board foot; softwood is often priced per piece or per lineal foot.
The formula, a worked example, the assumptions behind it and the sources are shown in full below the calculator.
Related calculators
- Lumber Calculator — Lineal feet and piece count of dimensional lumber for a job.
- Decking Calculator — Decking boards, joists and fasteners for a deck of a given size.
- Plywood Calculator — Sheets of plywood or OSB for a floor, wall or roof area.
Part of the Lumber & Wood calculators.