Board Foot Calculator
Calculate board feet and lumber cost. Enter board sizes and your supplier’s price below.
What is a board foot?
A board foot measures wood volume. Picture a piece 12 inches wide, 12 inches long, and 1 inch thick. That is one board foot (BF), or 144 cubic inches.
The formula gives the volume of one board. Multiply by the quantity for matching boards, then add the subtotals for different sizes. Four boards measuring 1 inch × 6 inches × 8 feet contain 16 BF. Add 10% extra and the planning total becomes 17.6 BF.
How to calculate lumber cost
Multiply the board feet you plan to buy by the price per board foot. In the example above, 17.6 BF at $6.50 per BF costs $114.40: $104.00 for the measured boards and $10.40 for the allowance. Replace the sample price with your supplier’s quote.
If a supplier quotes per board, divide that price by its board footage first. A 1-inch × 6-inch × 8-foot board contains 4 BF, so an example $24 per board is $6 per BF. Use the dimensions the seller bills. Changing currency converts your entered price; it does not look up lumber prices.
Convert a price per thousand board feet
A quote marked MBF means thousand board feet. Divide a lumber price per MBF by 1,000 before entering it here. An example $6,500 per MBF becomes $6.50 per BF. This changes the price unit, not the board dimensions or the seller’s measurement rules.
Board feet to cubic feet
Divide board feet by 12 to get cubic feet: 24 BF equals 2 ft³. To measure a rectangular space or packed item directly, use the cubic feet calculator.
Board foot formula and examples
Formula reference: Wood-Mizer: What is a board foot?
Common questions
Should I enter rough or finished dimensions?
For buying lumber, use the dimensions your supplier bills. For actual wood volume, use measured dimensions. The calculator uses your inputs without rounding them to nominal sizes.
How many board feet are in a 2 × 4 × 8?
Using 2 inches × 4 inches × 8 feet gives 5.33 BF. Using measured dimensions of 1.5 inches × 3.5 inches × 8 feet gives 3.5 BF. These answer different questions: nominal volume and actual volume.
How much extra lumber should I allow?
The amount depends on defects, trimming, grain selection and your cuts. The default 10% is an example. Check your cutting plan before ordering.
Can I calculate multiple board sizes?
Yes. Add a row for each size and enter its quantity. You can calculate up to 50 board sizes in one tally.
Is a board foot the same as a square foot?
No. Square feet measure area; board feet measure volume. A one-square-foot panel that is one inch thick is one board foot. The same panel at two inches thick is two board feet.
Does this estimate lumber from a round log?
No. It works with rectangular boards. Estimating sawn yield from a log requires a log rule and assumptions about taper, kerf, defects, and processing.
Questions about a result? See how our calculators are built or report a calculation issue.