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Board Foot Calculator

With thickness 1 inch, width 6 inch, length 8 ft, number of boards 10 and 1 more field, board foot comes to 40.00 bf — total board feet. It is reached in 4 steps, the last of which is 4 * 10, and each one is printed on the page with its numbers filled in. The formula is the one published by NIST Office of Weights and Measures, not an approximation fitted to it.

Convert lumber dimensions to board feet and price out a cut list, including nominal-vs-actual sizing.

Formula and sources checked · How we check

Thickness 1 inch, Width 6 inch, Length 8 ft, Number of boards 10

40.00 bf

Total board feet for the example below. Editing a field recomputes the calculator below; this figure holds the answer the page was loaded with.

It is written into the HTML rather than drawn by a script, so a search engine reading this page without running JavaScript still finds an answer.

Total board feet
40.00 bf
Board feet per board
1 * 6 * 8 / 124 bf
Total board feet
4 * 1040 bf
Total linear feet
8 * 1080 ft
Material cost
40 * 4.25170

Several at once

A job is rarely one of anything. Work out the first, add it, change the figures and add the next — the list keeps what each line was, and totals them.

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Worked example

Ten 1×6×8 boards are 40 board feet, not 80: the board foot formula uses nominal thickness and width in inches divided by 12, so 1 × 6 × 8 / 12 = 4 bf each. At $4.25/bf that is $170.

How to work it out yourself

  1. 1.Measure nominal thickness and width in inches and length in feet. Nominal is what the board is sold as, not what a tape reads after surfacing.
  2. 2.Multiply thickness by width by length, then divide by 12. That is one board foot per 144 cubic inches of nominal volume.
  3. 3.Multiply by the number of boards for the total.
  4. 4.Multiply the total by the price per board foot. Hardwood is priced this way; framing lumber is priced per piece.

The formula

  1. Board feet per board1 * 6 * 8 / 12
  2. Total board feet4 * 10
  3. Total linear feet8 * 10
  4. Material cost40 * 4.25

Source: NIST Office of Weights and Measures — methods of sale for lumber, American Lumber Standard Committee — nominal vs actual dimensions

Questions people actually ask

Should I use nominal or actual dimensions?
Lumber is sold by nominal size, so a "2×4" is billed as 2 in × 4 in even though it measures 1.5 in × 3.5 in after surfacing. Use nominal for pricing and actual only when checking whether a piece physically fits.
Why is 5/4 decking entered as 1.25?
Quarter sizing states thickness in quarters of an inch: 4/4 is 1 in, 5/4 is 1.25 in, 8/4 is 2 in. This calculator accepts either "5/4" or "1.25".
How do board feet differ from linear feet?
Linear feet measure only length; board feet measure volume. Two boards of the same length can differ 3× in board feet if one is a 1×4 and the other a 2×6, which is why hardwood is priced per board foot and framing lumber per piece.

Related

Part of a job

Read first

  • What a Deck Costs to Build — Decking, framing and fasteners priced out, and why the board decides the total: the framing under it barely changes between a cheap deck and a costly one.
  • What a Fence Costs — Post spacing, the ground-contact rating most people buy wrong, and why corners and gates cost more per foot than the long straight runs between them.

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