Board Foot Calculator

Build a lumber tally

Enter thickness and width in inches, length in feet, and a whole-board quantity. Add another row for each different size. The result lists each row’s board feet and the combined total. Enter a price per board foot if you want a material subtotal, then copy or download the tally.

A board foot measures volume

One board foot is 144 cubic inches: a board one inch thick, twelve inches wide and twelve inches long. With length entered in feet, the formula is thickness × width × length ÷ 12. Multiplying that result by quantity gives the row total. A board foot is neither a linear foot nor a square foot; thickness is part of the calculation.

Worked example: shelves in two sizes

One board measuring one inch thick, six inches wide and eight feet long contains four board feet. Three of those boards contain twelve board feet. Add two boards measuring two inches thick, eight inches wide and six feet long: each contains eight board feet, adding sixteen. The combined order is five boards and twenty-eight board feet. At 7.50 per board foot, the material subtotal is 210.

Choose the dimensions that match your purpose

For a geometric volume calculation, enter the measured dimensions. For a purchase estimate, ask how the seller tallies that stock. A nominal two-by-four is not necessarily two inches by four inches after surfacing. Rough hardwood sold as 4/4 or 8/4 may also use billing conventions that differ from the finished thickness you measure. This calculator does not silently substitute dressed sizes or round thickness up to a merchant’s minimum.

Assumptions and limits

Every row represents rectangular boards of one size. Decimal dimensions are accepted, but quantities must be whole numbers. Use decimal inches such as 0.75 rather than entering a fraction such as 3/4. The tool totals up to fifty rows and assumes the same unit price throughout the list. Separate runs are appropriate for different species, grades or prices.

The estimate does not lay out cuts, account for saw kerf, select grain, or reserve extra stock for defects and machining. A board with enough total volume may still be too short or too narrow for a particular part. Review your cut list independently, and keep offcuts and waste allowances separate from the dimensions of boards you intend to buy.

Board foot FAQ

Why is my supplier’s tally different?

Suppliers may round widths or lengths and use nominal thicknesses. Compare the written tally rules with the exact dimensions entered here. Hardwood Industries’ calculator documents an example of merchant rounding.

Does the price include delivery?

No. It is simply total board feet multiplied by your entered rate, without tax, delivery or milling charges. Nothing is fetched from a pricing service.