Board Feet to Linear Feet Conversion Explained

Convert board feet to linear feet by dividing the total board feet by the thickness in inches and then by the width in inches, then multiplying by 12. Enter the board feet, thickness, and width into the calculator below to get the linear feet instantly.

Formula

The formula to convert board feet to linear feet is:

Linear Feet = (Board Feet ÷ (Thickness × Width)) × 12

Where:

• Board Feet – volume measure, 1 board foot = 1 ft × 1 ft × 1 in (144 cubic inches)
• Thickness – board thickness in inches
• Width – board width in inches
• Linear Feet – length of the board in feet, assuming the board is cut to the given width and thickness

This formula works because board feet measure volume, while linear feet measure length. Dividing the volume by the cross-sectional area (thickness × width) gives the length in inches, then converting to feet by dividing by 12.

Worked Example

Using the default values from the calculator: 100 board feet, 1-inch thickness, 6-inch width.

1. Calculate cross-sectional area: 1 in × 6 in = 6 in²
2. Divide board feet by area: 100 ÷ 6 = 16.6667
3. Multiply by 12 to convert to feet: 16.6667 × 12 = 200 linear feet

The result is 200 linear feet. This matches the calculator output.

When to Use This Conversion

This conversion is common in woodworking, lumber purchasing, and construction. You often buy lumber by the board foot (volume), but you need to know the total length of boards to plan cuts, estimate trim, or calculate how many pieces you can get from a stack.

For example, if you have 500 board feet of 2×4 lumber (actual 1.5″ × 3.5″), you can calculate the linear feet to know how many 8-foot studs you can cut. The calculator simplifies this, but understanding the math helps when you’re at the lumber yard without a calculator.

Common Mistakes and Misconceptions

A frequent error is forgetting to convert thickness and width to inches when they are given in different units. Always use inches for both dimensions and board feet for volume. Another mistake is confusing board feet with linear feet – they measure different things. Board feet is volume (length × width × thickness), while linear feet is just length.

Also, note that nominal lumber sizes differ from actual sizes. A 2×4 is actually 1.5″ × 3.5″. Using nominal sizes will give incorrect linear feet. Always use the actual dimensions for accurate results.

How to Choose the Right Inputs

To get accurate linear feet, you need to know:

• Total board feet of lumber you have or need
• Actual thickness of each board (measure it, don’t rely on nominal)
• Actual width of each board

If you have boards of different sizes, calculate each size separately and sum the linear feet. The calculator assumes uniform thickness and width. For mixed stock, do separate conversions.

Practical Examples

Let’s look at a few scenarios:

• 1×6 lumber: 100 board feet ÷ (1″ × 6″) × 12 = 200 linear feet (as in the example)
• 2×4 lumber: 100 board feet ÷ (1.5″ × 3.5″) × 12 ≈ 228.57 linear feet
• 1×12 lumber: 100 board feet ÷ (1″ × 12″) × 12 = 100 linear feet

Notice that thicker or wider boards yield fewer linear feet for the same board feet, because volume is spread over a larger cross-section.

Limitations and When to Use Other Measures

This conversion assumes the board has a consistent rectangular cross-section. If you have tapered or irregular lumber, the formula won’t be exact. Also, if you need to account for waste due to cutting, add a waste factor (e.g., 10% extra) to your board feet before converting.

For projects where you only need length (like trim or molding), you might skip board feet entirely and buy by linear foot. But when ordering from a sawmill or in bulk, board feet is standard, so this conversion is essential.

Frequently Asked Questions

What is a board foot?

A board foot is a volume measurement equal to a board that is 1 foot long, 1 foot wide, and 1 inch thick (144 cubic inches). It’s used to price lumber, especially hardwoods.

What is a linear foot?

A linear foot is simply a length of 12 inches, regardless of width or thickness. It measures length only, not volume.

Can I convert linear feet to board feet?

Yes, multiply linear feet by the thickness (in inches) and width (in inches), then divide by 12. For example, 10 linear feet of 1×6 (actual 1″×6″) = 10 × 1 × 6 / 12 = 5 board feet.

Does nominal size matter?

Yes, nominal sizes are approximate. A 2×4 is actually 1.5″ × 3.5″. For accurate conversions, always use the actual dimensions, not the nominal ones.

How many linear feet are in 100 board feet of 2×6?

Assuming actual dimensions of 1.5″ × 5.5″, the linear feet = (100 / (1.5 × 5.5)) × 12 ≈ 145.45 linear feet.

Is this conversion the same for metric?

No, the formula changes if you use metric units. Board feet is an imperial unit. For metric, you’d use cubic meters and meters, with a different formula. This calculator is for imperial only.

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in bf | Board feet | bd ft | 100 | 0
in t | Thickness | in | 1 | 0
in w | Width | in | 6 | 0
out lf | Linear feet | ft | (bf / (t * w)) * 12 | 2