Board Foot Calculator
Calculate board feet for dimensional lumber purchases.
Calculate your estimate
Planning estimate only. Verify manufacturer specifications, local codes and project measurements.
Measure lumber using the correct mixed units
- Enter board thickness and width in inches, then length in feet. The formula deliberately uses different units for cross-section and length.
- Enter a whole number of identical boards. Calculate each size group separately when the order contains different thicknesses, widths or lengths.
- Select Calculate for total board feet. Match your dimensions to the supplier’s tally method before using the result to compare prices.
Board Foot Calculator: formula and assumptions
Board feet = thickness in inches × width in inches × length in feet × number of boards ÷ 12.
Worked calculation
Twelve boards at 2 in × 8 in × 10 ft contain 160.00 board feet.
What this estimate includes
Choose actual or nominal dimensions consistently with your supplier’s pricing method. Enter a whole number of boards. This measures lumber volume, not structural capacity.
Planning details that change the estimate
A board foot measures volume: a 1-inch-thick board, 12 inches wide and 1 foot long contains one board foot. It is different from a linear foot and from a square foot of surface coverage. Nominal and surfaced dimensions can produce different totals, so state which basis you used. The calculator does not add allowance for defects, trimming, planing or selection; include those separately in your lumber takeoff.
Board Foot Calculator FAQs
Should I enter nominal or actual dimensions?
Use the dimensions that match the supplier’s pricing and tally convention. Do not mix nominal thickness with measured width without checking the basis.
How do I calculate mixed board sizes?
Run each group of identical boards separately and add the board-foot totals. Do not average dimensions when boards differ significantly.
Does the result tell me how many deck boards to buy?
No. Board feet is volume. Deck coverage also depends on board face width, gaps, layout and lengths.
Can I estimate lumber cost from this result?
Multiply total board feet by a verified price per board foot on the same dimensional basis. The calculator itself does not include a price field.
Continue planning this project
Use the Deck Board Calculator for deck surface coverage, the Wall Stud Calculator for wall framing counts, and the Rafter Calculator for roof-member geometry.
RESULTS