Board Feet Calculator
Calculate board feet for a whole lumber list, with waste factor, price per board foot and CSV export.
Thickness and width in mm, length in cm — the usual way timber is quoted.
Enter thickness, width and length for a board — the board footage updates as you type.
- Total board feet
- 5.333
- With waste factor
- 5.333
- Estimated cost
- —
- Pieces
- 1 piece
- Volume (cubic feet)
- 0.444 ft³
- Volume (cubic metres)
- 0.0126 m³
How it works
Lumber is traditionally tallied with nominal sizes: a 2×4 counts as 2 in × 4 in even though it actually measures 1½ in × 3½ in. Use nominal figures when you are pricing construction lumber, and the real measured sizes when you are tallying rough-sawn or surfaced hardwood.
A board foot is a volume: 144 cubic inches of lumber — a piece 1 inch thick, 12 inches wide and
1 foot long. This calculator uses the standard formula
board feet = thickness(in) × width(in) × length(in) ÷ 144, which is the same as
thickness(in) × width(in) × length(ft) ÷ 12. So one 2×4×8 ft stud is
2 × 4 × 8 ÷ 12 = 5.333 board feet, and a 1×6 board 10 ft long is exactly 5 board feet.
Quantities multiply the row, so ten 2×4×8s come to 53.333 board feet.
Add a row per size, set a waste/overage percentage for offcuts and defects, and enter your yard's price per board foot to get a running cost. In metric mode you enter thickness and width in millimetres and length in centimetres; everything is converted to inches internally (1 in = 25.4 mm) and the volume is also shown in cubic feet (board feet ÷ 12) and cubic metres (1 board foot = 0.002359737 m³). Hardwood thickness is often quoted in quarters — 4/4 is 1 in, 5/4 is 1.25 in, 8/4 is 2 in — and the size picker fills those in for you. Everything runs in your browser: nothing is uploaded, there are no sign-ups and no ads.
Frequently asked questions
How do you calculate board feet?
A board foot is 144 cubic inches of lumber, which is 1 inch thick, 12 inches wide and 1 foot long. The formula is board feet = thickness(in) x width(in) x length(in) / 144, the same as thickness(in) x width(in) x length(ft) / 12. Multiply by the number of pieces of that size.
How many board feet are in a 2x4x8?
5.333 board feet, because 2 x 4 x 8 / 12 = 5.333. Ten of them come to 53.333 board feet. Lumber is tallied at nominal size, so a 2x4 counts as 2 in x 4 in even though it really measures 1.5 in x 3.5 in.
Should I use nominal or actual sizes?
Use nominal sizes for construction lumber, because that is how yards price it, so a 2x6 is figured as 2 in by 6 in. Use the real measured thickness and width for rough-sawn or surfaced hardwood, where thickness is quoted in quarters (4/4 = 1 in, 5/4 = 1.25 in, 8/4 = 2 in).