Board Foot Calculator
Lumberyards price hardwood by the board foot — a volume unit equal to a piece 12 in × 12 in × 1 in thick. It's not intuitive (a 2×4 eight feet long is not "8 board feet"), and getting it wrong means a 30% surprise at the register.
Enter the nominal thickness and width in inches, the length in feet, and how many boards you need. Note: hardwood is sold by NOMINAL size — a dressed 4/4 board is actually about 13/16 in thick, but it's counted as a full inch.
Nominal: 1 in (4/4), 1.5 in (6/4), 2 in (8/4)
- Board feet per board
- 6 bd ft
- Total board feet
- 60 bd ft
- Lumber cost (est.)
- $90 – $360
Cost range spans common construction softwood to mid-range hardwoods. Premium hardwoods (walnut, cherry, figured stock) can run $8–$20+ per board foot.
How This Calculator Works
Board feet = Thickness(in) × Width(in) × Length(ft) ÷ 12 × Quantity- Use the NOMINAL thickness and width (what you order), not the dressed/actual size.
- Multiply thickness × width in inches, then by length in feet.
- Divide by 12 — that's board feet for one board.
- Multiply by the number of boards and round to two decimals (lumberyards bill to the nearest 0.01 or 0.25 bd ft).
Example: Ten boards of 6/4 (1.5 in) cherry, 6 in wide, 8 ft long: 1.5 × 6 × 8 ÷ 12 = 6 bd ft each → 60 board feet total.
Frequently Asked Questions
What is a board foot of lumber?
A board foot is a volume of 144 cubic inches — a board 12 in wide × 12 in long × 1 in thick. Hardwoods and thicker slab lumber are priced per board foot, while construction softwoods (2×4s etc.) are priced per piece or per linear foot.
How do I calculate board feet for a 2×4?
Using nominal size: 2 × 4 × 8 ÷ 12 = 5.33 board feet per 8-footer. But big-box 2x4s are sold by the piece; the board-foot price matters mainly at hardwood yards and for bulk framing lumber quotes.
Nominal vs actual lumber size — which do I use?
Always calculate board feet with the NOMINAL (named) size: a 1×6 is really ¾ in × 5½ in dressed, but it's billed as a full 1 in × 6 in. Using actual sizes undercounts your bill by 20–25%.
How much does lumber cost per board foot in 2026?
Construction softwood framing runs roughly $1.50–$4 per board foot, common hardwoods (oak, maple, poplar) $4–$8, and premium woods (walnut, cherry) $8–$20+. Rough-sawn is cheaper than S4S (surfaced four sides), which the mill charges extra for.
What does 4/4, 5/4, 8/4 lumber mean?
That's thickness in quarters of an inch: 4/4 = 1 in nominal (about 13/16 in dressed), 5/4 = 1.25 in, 8/4 = 2 in. Hardwood is ordered in these quarter designations, and board feet use the nominal quarter size.
Related Calculators
Last updated: 2026-10-26