What is a board foot?

A volume of lumber equal to 144 cubic inches, a piece 1 in thick, 12 in wide and 12 in long. In feet and inches it is thickness in inches x width in inches x length in feet / 12.

Do I use nominal or actual sizes?

Nominal. A 2x4 is actually 1-1/2 x 3-1/2 in, but board feet for dimensional lumber are figured on the nominal 2 x 4.

What lengths does lumber come in?

Dimensional lumber is stocked from 8 to 20 ft in 2 ft steps, with 8, 10, 12, 14 and 16 ft the most common.

Board feet or linear feet?

Both are shown, plus the piece count, so you can match however your lumberyard prices the list. Linear feet are the quantity times the length of each line.

Is this number a quote?

No. It is an estimate to help you plan and build your bid. Confirm the final quantity with your supplier before you order.

Free calculator

Board foot calculator

Board feet = thickness in inches x width in inches x length in feet, divided by 12. One 2x6 at 10 ft is 2 x 6 x 10 / 12 = 10 board feet.

Your job

Lumber list (nominal sizes)

Line 1 quantity

Thick

Wide

Long

Line 2 quantity

Thick

Wide

Long

A 2x6 is entered as 2 and 6 (nominal), not its actual 1-1/2 x 5-1/2 in.

Waste (optional)

Waste factor0%

No standard figure: set your own allowance for culls and cutoffs, or leave it at 0.

One board per line, lengths to scale.

Board feet

280.00BF

Thickness x width x length / 12, added up

Linear feet

216.0LF

Pieces

18pieces

The working, with your numbers

1. Line 112 x 2.00 x 6.00 x 10.00 / 12= 120.00 BF
2. Line 26 x 2.00 x 10.00 x 16.00 / 12= 160.00 BF
3. Total120.00 + 160.00= 280.00 BF

Typed those measurements in by hand?MetreMate measures them straight off your PDF plans. Free to start.

The formula, in plain words

1Board feet per piece = thickness in inches times width in inches times length in feet, divided by 12.
2Use nominal sizes (a 2x6 is figured as 2 x 6, not its actual 1-1/2 x 5-1/2 in).
3Board feet per line = board feet per piece times the quantity.
4Total = the sum of every line, plus your waste if you add one.

Worked example

12 pieces of 2x6 at 10 ft and 6 pieces of 2x10 at 16 ft.

1.One 2x6 at 10 ft: 2 x 6 x 10 / 12 = 10 BF.
2.12 of them: 12 x 10 = 120 BF.
3.One 2x10 at 16 ft: 2 x 10 x 16 / 12 = 26.67 BF.
4.6 of them: 6 x 26.67 = 160 BF.
5.Total: 120 + 160 = 280 BF.

Answer: 280 board feet (216 linear feet in 18 pieces).

Measured this off a plan? Do it in MetreMate

Upload the PDF, set the scale and measure on screen. MetreMate gives you the square feet, linear feet and counts off the plan; then you apply the thickness, pitch, waste or sheet size here. Runs in your browser, free to start, no credit card.

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How to measure it

Write the lumber list as quantity, nominal size and length, one line per size and length.
Thickness and width are the nominal inches (2x10 is 2 and 10). Length is in feet.

Where the numbers come from

Every default in the calculator comes from a published source. We list the source next to it so you can check.

What	Value	Source
One board foot (1 in x 12 in x 12 in); BF = T in x W in x L ft / 12, at nominal size	144 cu in	Board Foot Calculator, what is a board foot (checked 2026-09-20)
A nominal 2x4 is actually 1-1/2 x 3-1/2 in; board feet are figured on nominal size	1.5 x 3-1/2 in	Kreg Tool, understand lumber sizing (checked 2026-09-20)
Dimensional lumber stock lengths, in 2 ft steps (8, 10, 12, 14 and 16 ft most stocked)	8 to 20 ft	Hunker, standard lengths for dimensional lumber (checked 2026-09-20)

Manufacturers named here are the source of the number, not a recommendation. Confirm quantities with your supplier.

Frequently asked questions

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