Board Foot per Linear Foot

The Board Foot per Linear Foot calculator computes the board foot per linear foot  factor, which defines the ratio of the cross-sectional area of a board you measure to the standard board foot cross sectional area.

INSTRUCTIONS: Choose units and enter the following:

• (T) Thickness of the board
• (W) Width of the board

Board Feet per Linear Feet (BFpLF):  The calculator returns the ratio.

The Math / Science

Board footage (BF) is a measurement used for most lumber items and defines the wood volume per foot-length of any dimensioned board.  A nominal board foot is defined as a piece of lumber one inch thick by one foot wide by one foot long -- or its equivalent.  This equation's Board Foot per Linear Foot (BFpLF) factor provides the multiplicative factor to generate an "equivalent" multiplier for a board foot of a dimensioned wood.

Linear measure is a measurement of the total length in feet of a board; the linear measurement is not dependent on the thickness or width.

The BFpLF factor computed by this equation is calculated by multiplying the thickness (T) by the width (W) and dividing by the standard cross section of a nominal board foot .  The resulting factor is unit-less as it is the ratio of the cross sectional area of the measured board to the cross sectional area of a standard board foot.

The Board Foot per Linear Foot equation is:     

BFpLF = `(T * W) / "standard board foot"`

where:

• BFpLF = Board Foot per Linear Foot
• T = Board Thickness
• W = Board Width
• SBF = Standard Board Foot (0.0833333333333333 ft²)

EXAMPLES

The factor of board feet per lineal foot allows for calculating board footage for odd sized lumber.  

EXAMPLE 1: As an example; using the formula - a lineal foot of  a 2 by 10 (2X10) has a BFpLF value of approximately 1.66666666666667.

Using the BFpLF factor calculated by this equation to compute the board feet of a 20 foot 2X10, we would just multiply the calculated BFpLF factor by the total length of the our example 2X10.

     `"Total BF" = 20 "Linear Feet"  * 1.67  "Board Feet per Linear Foot" = 33.33 "Board Feet"`

So, a 20 foot 2X10 is approximately 33-1/3 BF.

EXAMPLE 2:  Charley routinely buys large loads of standard lumber, which he uses to produce custom built cabinets.  Since the lumber Charley buys are 2X6s, the actual standard dimensions are 1-1/2 inches X 5-1/2 inches.  He enters the inputs:

• T = 1.5
• W = 5.5

to computes the Board Foot per Linear Foot factor to be:  BFpLF = 0.6875

This means that for every linear foot of lumber he purchases he gets 0.6875 board feet.

His weekly shipment is two hundred and twenty 12-foot 2X6s and Charley multiplies to determine he is purchasing every week:  `(0.6875 "BFpLF") * 220 "boards" * 12 "ft/board" = 181.5 "BF"`

Lumber Calculators

• Board Feet Calculator - computes the board feet of a number of measured boards
• Board Foot per Linear Foot - computes the board foot per linear foot  factor.

Lumber Constants (Data)

• Standard Boar Foot