Board Foot Calculator – Free Lumber Volume Tool

Board Foot Calculator

Instantly calculate lumber volume in board feet — single board or full project list.

Formula: BF = (Thickness″ × Width″ × Length″) ÷ 144 — ÷ 12 when Length is in feet

Length in:

All values in inches

Board Dimensions

Thickness

Width

Length

Quantity (boards)

Price per BF (optional)

What is a Board Foot?

A board foot is the standard unit of lumber volume in North America. It equals a piece of wood 1″ thick × 12″ wide × 12″ long (144 cubic inches). Hardwood is bought and sold in board feet; most dimensional softwood (2×4s, etc.) is sold by the linear foot.

When all dimensions are in inches:
BF = (Thickness″ × Width″ × Length″) ÷ 144

When length is in feet:
BF = (Thickness″ × Width″ × Length′) ÷ 12

Common Lumber Sizes

Nominal	Actual (in)	BF / ft
1 × 4	¾ × 3½	0.33
1 × 6	¾ × 5½	0.50
1 × 8	¾ × 7¼	0.67
1 × 10	¾ × 9¼	0.83
1 × 12	¾ × 11¼	1.00
2 × 4	1½ × 3½	0.67
2 × 6	1½ × 5½	1.00
2 × 8	1½ × 7¼	1.33
2 × 10	1½ × 9¼	1.67
4 × 4	3½ × 3½	1.33

Pro Tips

Always use actual dimensions, not nominal (a 2×4 is really 1.5″ × 3.5″).
Budget 10–15% extra material for cuts, waste, and defects.
Rough-sawn lumber is measured before planing — finished size is smaller.
Hardwood is priced per board foot; softwood is usually per linear foot.
Enter a price per BF above to instantly estimate total material cost.