Board Foot Calculator
Board feet = thickness (in) × width (in) × length (ft) ÷ 12. A 2 × 4 that is 8 feet long is 5.33 board feet, and an 8-foot 1 × 12 is 8.
Updated October 15, 2026 · How we calculate
Worked example
A deck frame list: ten 2 × 6 × 12 ft joists and three 1 × 6 × 8 ft trim boards.
- One joist: 2 × 6 × 12 ÷ 12 = 12 bf; ten of them = 120 bf
- One trim board: 1 × 6 × 8 ÷ 12 = 4 bf; three of them = 12 bf
- Total: 132 board feet
How to choose and how deep
Softwood: use the name size
Construction lumber is sold by its nominal size. A 2 × 4 is planed smaller than 2 by 4 inches, but board feet are still worked out from 2 and 4.
Source: American Softwood Lumber Standard, PS 20-20 (NIST)
Hardwood: quarters and rough thickness
Hardwood thickness is given in quarters of an inch: 4/4 is 1 inch, 5/4 is 1¼, 8/4 is 2. Board feet are measured before planing, so a 4/4 board surfaced to 13/16 inch is still tallied at 1 inch.
Source: NHLA Rules for the Measurement and Inspection of Hardwood (2023)
Thin stock
Boards thinner than 1 inch are counted as 1 inch thick.
Source: NHLA Rules for the Measurement and Inspection of Hardwood (2023); 7 CFR §1217.4 (softwood lumber board foot)
Quick reference
| Board | 8 ft | 10 ft | 12 ft | 16 ft |
|---|---|---|---|---|
| 1 × 6 | 4 | 5 | 6 | 8 |
| 1 × 12 | 8 | 10 | 12 | 16 |
| 2 × 4 | 5.33 | 6.67 | 8 | 10.67 |
| 2 × 6 | 8 | 10 | 12 | 16 |
| 2 × 8 | 10.67 | 13.33 | 16 | 21.33 |
| 2 × 10 | 13.33 | 16.67 | 20 | 26.67 |
| 2 × 12 | 16 | 20 | 24 | 32 |
| 4 × 4 | 10.67 | 13.33 | 16 | 21.33 |
Questions people ask
What is a board foot?
A piece of wood 12 inches wide, 12 inches long and 1 inch thick: 144 cubic inches.
Source: NHLA Rules for the Measurement and Inspection of Hardwood (2023)
How many board feet are in a 2 × 4 × 8?
5.33 board feet: 2 × 4 × 96 inches ÷ 144. Softwood is measured by its name size, not its planed size.
Source: American Softwood Lumber Standard, PS 20-20 (NIST)
Do you use the actual or the nominal size?
Softwood uses the nominal (name) thickness and width. Hardwood uses the rough thickness in quarters, so a 4/4 board planed to 13/16 inch still counts as 1 inch.
Source: American Softwood Lumber Standard, PS 20-20 (NIST); NHLA Rules for the Measurement and Inspection of Hardwood (2023)
How do you count boards thinner than 1 inch?
As 1 inch thick. The rule applies to hardwood and softwood tallies.
Source: NHLA Rules for the Measurement and Inspection of Hardwood (2023); 7 CFR §1217.4 (softwood lumber board foot)