As an Amazon Associate I earn from qualifying purchases.
How many boards to buy: linear feet or a cut list turned into stock-length 2x4s, 2x6s, 4x4s and more, with offcuts, board feet and cost.
With these inputs:
| Result | Value |
|---|---|
| 2x6 × 12 ft boards to buy | 22 boards |
| Linear feet with waste | 264 ft |
| Linear feet bought | 264 ft |
| Board feet | 264 bf |
| Boards | 240 ft × 1.10 ÷ 12 ft, rounded up |
| Actual size | 1.5 × 5.5 in actual (dry, dressed) |
Linear feet assume your pieces use up whole boards. If every piece is the same length, switch to the cut list — it counts the pieces each board really yields.
Lumber is sold by the piece in standard lengths, so a project's real question is how many boards of which length. Enter the total linear feet you need, or the length and number of identical pieces to cut, then the size and the stock length you'll buy. The calculator returns the boards, the offcut left on each one, the board feet and the cost at your price per board.
Add up the linear feet of each size, add 10% for waste, and divide by the board length you'll buy. 240 linear feet of 2x6 in 12 ft boards is 240 × 1.10 ÷ 12 = 22 boards. For identical pieces, count how many fit on each board instead.
Divide the board length plus one saw kerf by the piece length plus one kerf, and round down. With a 1/8 in kerf, an 8 ft (96 in) board gives two 40 in pieces with 15⅞ in left over, and a 12 ft (144 in) board gives three with 23¾ in left. Three 48 in pieces won't come out of a 12 ft board: the two cuts take the extra ¼ in.
In the US and Canada the standard lengths are 6, 8, 10, 12, 14, 16, 18, 20, 22 and 24 ft. Most yards stock 8–16 ft in common sizes; the longer lengths are usually special-order and cost more per foot.
1½ × 3½ in when dry and dressed. Lumber is named by its nominal size: a 2x6 is 1½ × 5½ in, a 2x8 1½ × 7¼, a 2x10 1½ × 9¼, a 2x12 1½ × 11¼ and a 4x4 3½ × 3½ in.
Whichever wastes least for your pieces. For 40 in pieces an 8 ft board yields two (15⅞ in left) but a 10 ft board also yields only two, because three pieces plus two kerfs need 120¼ in. Twenty pieces take ten 8 ft boards (80 ft) or seven 12 ft boards (84 ft), so compare the price per board — the cut list shows the offcut for each length.
Need the whole roof at once? The free roofing calculator works out roof area, squares, shingle bundles, underlayment, drip edge, ridge cap and installed cost from one set of measurements.