Buying wood by the right unit
Hardwood is sold by the board foot, sheet goods by the sheet, and firewood by the cord. Mixing them up is the quickest way to overpay. Use the board foot calculator for rough lumber, the plywood calculator for sheathing and subfloors, and the firewood cord calculator to check a delivery before you pay.
Which calculator should I use?
| You want to | Start here | What you get |
|---|---|---|
| Price lumber by the board foot | Board foot calculator | Board feet from thickness, width and length |
| Compare prices per piece and per board foot | Lumber cost calculator | Cost per board foot and per job |
| Cover a floor or wall with boards | Board feet to square feet calculator | Coverage for a given thickness |
| Count wall studs | Stud calculator | Studs at 16 or 24 inches on center |
| Buy plywood | Plywood calculator | 4x8 sheets for an area |
| Buy firewood | Firewood cord calculator | Cords from a stack size |
| Estimate log weight or yield | Log weight calculator and log board foot calculator | Weight by species, board feet by log rule |
Board feet in common boards
Board feet are thickness in inches times width in inches times length in feet, divided by 12.
| Board (nominal, in) | 8 ft | 10 ft | 12 ft | 16 ft |
|---|---|---|---|---|
| 1 × 6 | 4 | 5 | 6 | 8 |
| 1 × 12 | 8 | 10 | 12 | 16 |
| 2 × 4 | 5.33333 | 6.66667 | 8 | 10.6667 |
| 2 × 6 | 8 | 10 | 12 | 16 |
| 2 × 10 | 13.3333 | 16.6667 | 20 | 26.6667 |
| 4 × 4 | 10.6667 | 13.3333 | 16 | 21.3333 |
Lumber is sold by its nominal size, so a stated 2x4 measures smaller. These counts use the nominal size, as mills and yards do. See what a board foot is and the lumber dimensions chart.
Firewood by the cord
A full cord is a stack of 128 cubic feet. A face cord is one row of cut pieces, so it depends on the piece length. See face cord vs full cord before you compare prices.
Who runs this site
BoardFeetMath is published by Hassan Nawaz. The formulas are shown on each page and sources are listed where a page relies on them. How pages are checked is described in the editorial policy. If a number looks wrong, use the contact page and say which page and what you expected.