ContractorHandbook

Board Foot Calculator for Lumber Pricing

Thickness times width times length in feet, divided by 12. Use the nominal dimensions, the 2 and the 6 in a 2x6, not the real 1.5 by 5.5, because that is how the unit is defined and how the yard prices it.

thick, inwide, inlength, ftthickness x width x length / 12 = board feet
A board foot is a volume, not a length, and hardwood is priced in it. Thickness and width in inches, length in feet, divided by twelve, which is why a wide board costs more per foot of run than a narrow one of the same species.

Worked example

These are the figures the calculator opens with and the answer it gives. Change anything above and every number below moves with it.

  • Thickness, nominal2 in
  • Width, nominal6 in
  • Length12 ft
  • How many pieces20
  • Price per board foot, 0 to skip0 $

Total board feet240 bf

Board feet per piece12
Pieces20
Total board feet240
Total linear feet240 lf

What this calculator assumes

  • A board foot is nominal thickness times nominal width times length in feet, divided by 12. Use the nominal size, the 2 and the 6 in a 2x6, not the real 1.5 by 5.5.
  • Hardwood is sold by the board foot. Softwood framing is usually sold by the piece, so this is for pricing and for comparing two quotes written differently.

A board foot is a volume, not a length

One board foot is 144 cubic inches: a piece 1 inch thick, 12 inches wide, 12 inches long. A 2x6 twelve feet long is 2 x 6 x 12 / 12, which is 12 board feet.

That is why a linear foot price and a board foot price cannot be compared directly. Two quotes for the same job written in different units are not comparable until one is converted, and that conversion is what this page is for.

Hardwood, and the quarter system

Rough hardwood is sold in quarters of an inch: 4/4 is one inch, 5/4 is an inch and a quarter, 8/4 is two inches. That measurement is taken rough, before surfacing, so a 4/4 board surfaced two sides arrives at 13/16 and is still sold and priced as 4/4.

Random width hardwood is tallied board by board. If a supplier quotes $6.50 a board foot, the price is per board foot of rough measure, and what lands on your truck is thinner than the number.

Questions people ask

How do you calculate board feet?

Nominal thickness in inches times nominal width in inches times length in feet, divided by 12. A 2x8 ten feet long is 2 x 8 x 10 / 12, which is 13.33 board feet.

Do I use nominal or actual dimensions?

Nominal. A 2x4 counts as 2 by 4 even though it measures 1.5 by 3.5. That is the convention the whole lumber trade prices against.

How many board feet in a 2x4x8?

Five and one third. 2 x 4 x 8 divided by 12 equals 5.33 board feet.

Need the paperwork too?

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Common sizes, worked out

The same calculator with the numbers already filled in, one page per size, each ending in its own material list.

2x4x85.33 bf2x4x106.67 bf2x4x128 bf2x4x1610.67 bf2x6x88 bf2x6x1212 bf2x8x1216 bf2x10x1626.67 bf1x6x84 bf4x4x810.67 bf

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Contractor Handbook · https://contractorhandbook.com/calculators/board-foot-calculator/