How to use board feet and linear feet converter
What this calculation does
A linear-foot conversion is meaningful only when thickness and width stay fixed across the lumber being measured.
Choose the direction, enter the quantity, and use the same fixed cross-section dimensions for the whole calculation.
Enter the measurements
- Convert: Choose which quantity you need to convert using the fixed cross-section.
- Dimension basis: Select the dimension convention used by the product or quote; do not mix nominal labels with measured geometry.
- Board feet: Enter board feet for the forward conversion.
- Linear feet: Enter linear feet for the reverse conversion.
- Thickness: Enter the fixed thickness in inches.
- Width: Enter the fixed width in inches.
Formula and variables
LF = BF × 12 ÷ (thickness(in) × width(in)); BF = LF × thickness(in) × width(in) ÷ 12.
With cross-section in square inches, linear feet = BF×12÷(thickness×width); the reverse multiplies linear feet by thickness and width, then divides by 12.
Read the result
At a fixed 2×6 in cross-section, 24 BF corresponds to 24 linear feet.
Worked example
Inputs: 24 BF at fixed 2 in × 6 in cross-section
- Linear feet = 24×12÷(2×6).
- The result is 24 LF.
Expected result: 24 linear feet
Frequently asked questions
Can I use mixed cross-sections in one conversion?
No. Each result assumes one fixed thickness and width.
Does a nominal label always match actual dimensions?
No. Enter dimensions on the same basis as the quantity you intend to convert.
Conditions, presets and technical notes
Thickness and width must remain fixed. Use the same actual/nominal and trade/geometric basis as the source quantity. Do not interpret nominal softwood board measure as geometric volume.
Use one fixed cross-section and the same nominal or actual basis as the input quantity.