Board Feet to Linear Feet Converter

How to Convert Board Feet to Linear Feet

Board feet measure volume; linear feet (also written lineal feet in the trades) measure only length. To convert board feet to linear feet, you need the board's width — thickness is not required because it cancels out when you are going from volume back to a single dimension:

Example: 50 board feet of 6"-wide lumber = (50 × 12) ÷ 6 = 100 linear feet.

To go the other direction — from linear feet to board feet — you need both width and thickness, because you are now reconstructing volume from a length:

Example: 100 LF of 5/4×6 decking = (100 × 1.25 × 6) ÷ 12 = 62.5 board feet.

How to Use This Converter

The live converter above handles both directions in real time. Here is how each input works:

• Direction toggle: Choose BF → Linear Feet when you have a board-foot quantity and want running length. Choose Linear Feet → BF when you have a length and want volume.
• Value field: Enter the number of board feet (or linear feet, depending on direction).
• Width: Pick a standard width from the dropdown (2" through 12") or type any custom width into the text field. Use actual width for best accuracy — a nominal 1×6 is actually 5.5" wide.
• Thickness (LF → BF only): Enter the board thickness in inches. Defaults to 1". For 5/4 stock enter 1.25; for 2× framing enter 1.5.

The result and the full step-by-step formula update instantly as you type. No submit button required.

Why Width — and Not Thickness — Determines Linear Feet

When converting from board feet to linear feet, thickness drops out of the formula entirely. Here is why: a board foot is defined as a piece of wood 12 inches long, 12 inches wide, and 1 inch thick. When you ask "how many linear feet of 6"-wide board fit in 50 board feet?", you are asking how many 6"-wide, 12"-long sections exist in that volume — thickness does not affect that count as long as the board stays the same thickness throughout.

This means that 50 BF of 1×6, 50 BF of 2×6, and 50 BF of 4×6 are all exactly 100 linear feet at 6" wide. They are physically very different pieces of wood, but they produce the same running length. Only when you go the other direction — linear feet back to board feet — does thickness matter, because you are recalculating the full volume.

When You Need This Conversion

The BF ↔ LF conversion appears in several common situations:

• Fence boards — suppliers sell by the piece or lineal foot; you want to know how many board feet you are ordering, or vice versa.
• Deck boards — your deck plan shows linear feet of board runs; lumber is priced per board foot at the yard.
• Trim and molding — molding is sold by the linear foot, but a mill or specialty supplier may quote in board feet.
• Hardwood strips — narrow hardwood strips for tabletops or flooring are often priced per lineal foot but tallied in BF at the hardwood yard.
• Framing takeoffs — a structural engineer or estimator may specify lumber in BF; converting back to linear feet tells you how many full-length boards to pull from inventory.
• Contractor quotes vs cut lists — a supplier quotes 300 BF of 2×6 framing; your cut list is in linear feet. Convert to confirm quantities match before accepting the order.
• Custom-width hardwood for flooring — the wood floor plan is drawn in linear feet of run; the kiln-dried stock is sold in BF. Convert to price the job accurately.

Worked Examples

Example 1 — Fence boards: You have 200 BF of 6"-wide dog-eared fence boards (1" thick). How many linear feet of fence will they cover?
(200 × 12) ÷ 6 = 400 LF

Example 2 — Deck boards: Your deck needs 320 LF of 5/4×6 decking (1.25" thick, 6" wide). How many BF?
(320 × 1.25 × 6) ÷ 12 = 200 BF

Example 3 — Trim: You need 180 LF of 3/4" × 4" casing. How many BF?
(180 × 0.75 × 4) ÷ 12 = 45 BF

Example 4 — Hardwood tabletop strips: You plan a glue-up tabletop using 8 strips of 5/4×3 walnut, each 7 feet long. You measured in LF; the dealer quotes in BF. How many BF do you need?
Total LF = 7 × 8 = 56 LF. Board feet = (56 × 1.25 × 3) ÷ 12 = 17.5 BF. Add 10–15% for waste when ordering rough stock.

Board Feet vs Linear Feet: Key Difference

A 10-foot 1×4 and a 10-foot 2×6 are both 10 linear feet. But they contain very different amounts of wood: the 1×4 is 3.33 BF, the 2×6 is 10 BF. Linear feet measures only length — it ignores width and thickness entirely. Board feet captures all three dimensions and is therefore a true measure of wood volume.

This is why lumber quantities for mixed-dimension projects are typically specified in board feet (or pieces × dimensions), not linear feet. Using only linear feet to order lumber for a project with multiple board sizes will give you the wrong quantities.

Practical rule of thumb: if your project uses one standard size throughout (all 2×4 framing, all 1×6 decking), linear feet is a convenient shorthand. The moment you mix sizes — or buy from a hardwood yard where every board is a different width — work in board feet.

Nominal vs Actual Dimensions and Why They Matter

Dimensional lumber is sold by nominal size (e.g., 1×6) but measures smaller in actual cross-section (0.75" × 5.5"). This matters for board foot calculations:

• 50 BF of nominal 1×6 at 6" wide → (50 × 12) ÷ 6 = 100 LF
• 50 BF of actual 1×6 at 5.5" wide → (50 × 12) ÷ 5.5 ≈ 109 LF

That is a 9% difference — enough to matter on a large order. Hardwood dealers almost always sell by actual (rough-sawn) dimensions, not nominal. Softwood home centers use nominal pricing but sell actual sizes. Always confirm with your supplier which they are quoting before you convert and order.

The converter above accepts any width value, so enter the actual width in inches for the most accurate result.

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