The board-foot is a specialized unit of measure for the volume of lumber in the United States and Canada. It is the volume of a one-foot length of a board one foot wide and one inch thick.

Board-foot can be abbreviated FBM (for "foot, board measure"), BDFT, or BF. Thousand board-feet can be abbreviated as MFBM, MBFT or MBF.

In Australia and New Zealand the term super foot or superficial foot was used to mean the same.

One board-foot equals:

Board foot is the unit of measure for rough lumber (before drying and planing with no adjustments) or planed/surfaced lumber. An example of planed lumber is softwood 2x4 lumber one would buy at a large lumber retailer. The 2x4 is actually only 1+¹⁄₂ × 3+¹⁄₂ in (38 × 89 mm) but the dimensions for the lumber when purchased wholesale could still be represented as full 2x4 lumber, although the "standard" can vary between vendors. This means that nominal lumber includes air space around the physical board when calculating board feet in some situations, while the true measurement of "board feet" should be limited to the actual dimensions of the board.