Board Foot to Linear Foot Converter
Convert board feet of lumber to linear feet for any thickness and width. Free board foot to linear foot converter with the exact formula and a worked example.
Updated 2026-06-14 · Free · No sign-up · Runs privately in your browser
Show the formula & steps
How the Board Foot to Linear Foot Converter Works
Lumber is often priced by the board foot (a volume measure) but purchased by the linear foot (a length). This converter bridges the two: enter how many board feet you have plus the board’s thickness and width in inches, and it returns the equivalent linear feet (and inches) of that exact board profile.
The Formula
A board foot is 144 cubic inches of wood. The board-foot formula is:
Board feet = (thickness in × width in × length ft) ÷ 12
Rearranging to solve for length gives the conversion this tool performs:
Linear feet = (board feet × 12) ÷ (thickness × width)
The factor of 12 reconciles the foot-based length with the inch-based thickness and width so the units cancel cleanly.
Worked Example
You have 20 board feet of 1 in thick × 6 in wide lumber:
- Linear feet = (20 × 12) ÷ (1 × 6)
- = 240 ÷ 6
- = 40 linear feet
So those 20 board feet stretch out to 40 feet of 1×6 board — or 480 linear inches.
Common Conversions
| Board profile (thickness × width) | Linear feet per board foot |
|---|---|
| 1 in × 4 in | 3.00 |
| 1 in × 6 in | 2.00 |
| 1 in × 8 in | 1.50 |
| 2 in × 6 in | 1.00 |
Why This Conversion Matters
Sawmills and hardwood dealers quote prices per board foot, but the framing, trim or flooring you actually install is measured in linear feet. Converting between them lets you check that a quote matches your cut list, compare suppliers fairly, and avoid over- or under-ordering. Just be consistent about whether you use nominal or actual dimensions, since the difference can change your linear-foot total by a third or more.
Frequently asked questions
How do I convert board feet to linear feet?+
Multiply the board feet by 12, then divide by the product of the board's thickness and width in inches. The formula is linear feet = (board feet × 12) ÷ (thickness × width). For 20 board feet of 1 in × 6 in stock, that is (20 × 12) ÷ (1 × 6) = 40 linear feet.
What is the difference between a board foot and a linear foot?+
A board foot is a measure of volume — 144 cubic inches, equal to a 12 in × 12 in × 1 in piece — used to price lumber. A linear foot measures length only, ignoring thickness and width. To convert between them you must know the board's cross-section (thickness and width).
Why do you multiply by 12 in the conversion?+
Board feet are defined per foot of length, but the underlying formula uses length in feet while thickness and width are in inches. Multiplying by 12 converts the foot-based result back into the inch-based dimensions so the units cancel correctly, leaving an answer in feet of length.
How many linear feet are in a board foot of 1x6 lumber?+
For nominal-but-treated-as-actual 1 in × 6 in lumber, one board foot equals (1 × 12) ÷ (1 × 6) = 2 linear feet. So 10 board feet of 1×6 is 20 linear feet. Note that nominal lumber sizes are smaller than their stated size, so use actual dimensions for a precise result.
Should I use nominal or actual lumber dimensions?+
Lumber is sold by nominal size (a 2x4 is really about 1.5 in × 3.5 in), but board-foot pricing for rough or hardwood lumber usually uses the actual measured thickness and width. Use whichever dimensions your supplier quotes; for surfaced softwood, the actual dimensions give a more accurate conversion.