Lumber Board Feet Calculator
Calculate board feet for any quantity of lumber. Useful for hardwood pricing, framing estimates, and project cost-out.
What this calculates
Lumber is sold by board foot — a unit of volume equal to one square foot of board one inch thick. Hardwood pricing especially uses board feet. This calculator converts pieces of any size into total board feet so you can price out a project against lumberyard rates.
Formula & how it works
Board feet (single piece) = (thickness_in × width_in × length_in) ÷ 144, or equivalently (thickness × width × length_ft) ÷ 12. For multiple pieces of same size: multiply by quantity. Quarter notation: '4/4' = 1 inch thick rough (≈ ¾ inch after surfacing); 8/4 = 2 inches rough.
Worked example
Ten boards of 1×6 lumber, 8 feet long. Each board = (1 × 6 × 8) / 12 = 4 bd ft. Total = 40 bd ft. At $5/bd ft (typical for select hardwood), that's $200. Compare with construction lumber sold by 'piece' or 'linear foot' — same volume, different pricing units.
Frequently asked questions
Nominal vs actual dimensions?
Construction lumber is named nominally — a 2×4 is actually 1.5×3.5 inches after planing. Board-foot calculations traditionally use nominal dimensions. Hardwood is usually sold by actual rough dimensions.
What's 4/4 lumber?
Quarter notation for hardwood thickness. 4/4 = 1 inch (rough). 5/4 = 1.25 inches. 8/4 = 2 inches. After surfacing both sides (S2S), thickness shrinks ~25 %.
How do I price hardwood?
Quoted as $X per board foot. Same species varies by grade (FAS, Select, #1 Common). Domestic hardwoods $5–15 bd ft; exotics can hit $50+ bd ft.
Should I order extra?
Add 10–15 % for crosscuts, defects, and grain selection. Some figured woods need 25 %+ extra to get matched boards. Always ask the yard about return policy first.