Calculator · Lumber & cost
Board Foot to Linear Foot Calculator
Convert board feet to linear feet and back for any lumber size, on nominal or dressed dimensions, with metres, cubic metres and a quick table for common sizes.
Board foot to linear foot converter
Convert board feet to linear feet, or back, for a known thickness and width. Results also show metres and cubic metres.
Result
Enter a quantity and a lumber size, then calculate.
How many linear feet in one board foot?
Linear feet = 12 ÷ (thickness × width). Nominal is how lumber is tallied; dressed is the PS 20 Table 3 size.
| Size | BF per linear ft | Linear ft per BF (nominal) | Dressed size | Linear ft per BF (dressed) |
|---|---|---|---|---|
| 1x2 | 0.167 | 6 | 3/4 × 1-1/2 in | 10.667 |
| 1x3 | 0.25 | 4 | 3/4 × 2-1/2 in | 6.4 |
| 1x4 | 0.333 | 3 | 3/4 × 3-1/2 in | 4.571 |
| 1x6 | 0.50 | 2 | 3/4 × 5-1/2 in | 2.909 |
| 1x8 | 0.667 | 1.5 | 3/4 × 7-1/4 in | 2.207 |
| 1x10 | 0.833 | 1.2 | 3/4 × 9-1/4 in | 1.73 |
| 1x12 | 1 | 1 | 3/4 × 11-1/4 in | 1.422 |
| 2x2 | 0.333 | 3 | 1-1/2 × 1-1/2 in | 5.333 |
| 2x3 | 0.50 | 2 | 1-1/2 × 2-1/2 in | 3.2 |
| 2x4 | 0.667 | 1.5 | 1-1/2 × 3-1/2 in | 2.286 |
| 2x6 | 1 | 1 | 1-1/2 × 5-1/2 in | 1.455 |
| 2x8 | 1.333 | 0.75 | 1-1/2 × 7-1/4 in | 1.103 |
| 2x10 | 1.667 | 0.60 | 1-1/2 × 9-1/4 in | 0.865 |
| 2x12 | 2 | 0.50 | 1-1/2 × 11-1/4 in | 0.711 |
| 4x4 | 1.333 | 0.75 | 3-1/2 × 3-1/2 in | 0.98 |
| 6x6 | 3 | 0.333 | 5-1/2 × 5-1/2 in | 0.397 |
How it works
A board foot is a volume and a linear foot is a length, so converting between them needs the cross-section of the board. Once thickness and width are fixed, each foot of length holds the same number of board feet, and the conversion becomes a single multiplication or division.
Softwood lumber is tallied on its nominal size. The American Softwood Lumber Standard defines board measure using the nominal thickness and width, so a 2x4 counts as 2 × 4 in even though the dressed board is 1-1/2 × 3-1/2 in. The converter does that by default and lets you switch to the dressed size when you want the wood actually in the board, for example to estimate weight.
Results are given in linear feet, linear metres, board feet and cubic metres. The cubic-metre line under the nominal tally is the volume the invoice implies; the actual-volume line uses the dressed size.
- Board feet per linear foot = thickness (in) × width (in) / 12.
- Linear feet = board feet / board feet per linear foot = board feet × 12 / (thickness × width).
- Board feet = linear feet × thickness × width / 12.
- Linear metres = linear feet × 0.3048. Cubic metres = board feet × 0.002359737 (144 in³ × 0.0254³ m³/in³).
- Actual volume = dressed thickness × dressed width × length, in cubic inches, × 0.0254³.
Worked example
A supplier quotes 50 board feet of 1x6 boards. Each linear foot of nominal 1 × 6 in holds 1 × 6 / 12 = 0.50 board feet, so 50 board feet is 50 / 0.5 = 100 linear feet, or 30.48 m of board.
On the dressed 3/4 × 5-1/2 in size those 100 feet contain 0.0811 m³ of wood, against the 0.118 m³ implied by the nominal tally.
Going the other way, twelve 8 ft 2x4s are 96 linear feet: 96 × 2 × 4 / 12 = 64 board feet on the nominal tally.
Common mistakes
- Converting length to board feet without a thickness and width.
- Using the dressed size when the lumberyard bills on the nominal size, or the reverse.
- Mixing inches and feet: thickness and width in inches, length in feet.
- Treating a hardwood quarter thickness such as 4/4 as a dressed size; confirm the basis with the supplier.
- Applying a waste allowance twice, once to the length and again to the board feet.
Scope and limits
- Converts quantities for one cross-section at a time; mixed sizes need one conversion each.
- Dressed sizes are PS 20 Table 3 minimum dressed dry sizes for North American softwood. Green, rough, metric or hardwood stock can differ: enter a custom size.
- No waste, grade, defect or price allowance is applied.
Common questions
How many linear feet are in a board foot?
It depends on the size. Divide 12 by thickness × width in inches: a 1x6 gives 2 linear feet per board foot, a 2x4 gives 1.5, a 2x6 gives 1 and a 2x12 gives 0.5 on the nominal size.
Are board feet calculated on nominal or actual size?
For softwood lumber, the American Softwood Lumber Standard defines board measure on the nominal thickness and width, so a 2x4 is tallied as 2 × 4 in. Hardwood and rough lumber can be tallied differently, so check how your supplier counts.
How do I convert board feet to metres?
Find the linear feet first, then multiply by 0.3048. For volume, one board foot is 0.00236 m³, or about 424 board feet per cubic metre.
Why does the actual volume come out smaller?
Because a dressed board is smaller than its nominal name. A 2x4 has 5.25 in² of cross-section instead of 8 in², so it holds about two-thirds of the wood its tally suggests.
Sources
- Voluntary Product Standard PS 20-20: American Softwood Lumber Standard (Revision 1, October 2021)U.S. Department of Commerce, NISTSection 2.2, board measure: board feet are the nominal thickness in inches times the nominal width in feet times the length in feet. Section 4.1: lumber is tallied by board measure or cubic measure, and dressed sizes are used for cubic measure. Table 3 gives the minimum dressed dry sizes used for the dressed option, and Appendix B warns that nominal board feet and dressed cubic metres are not the same volume.
- Valuing Standing TimberPenn State ExtensionDefines the board foot as 144 cubic inches, a piece 1 in thick, 12 in wide and 12 in long.
- NIST Guide to the SI, Appendix B.9: Factors for units listed by kind of quantityNational Institute of Standards and Technology1 ft = 0.3048 m exactly and 1 ft² = 0.09290304 m², so 1 in = 0.0254 m and 1 board foot = 144 × 0.0254³ = 0.002359737 m³.