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Board Foot Calculator

Convert lumber dimensions to board feet and get a price — the way sawmills and hardwood dealers sell wood.

Board Foot Calculator

Board feet (and m³) of lumber for up to three board sizes, with waste, weight and cost.

How this is calculated

Board feet = thickness (in) × width (in) × length (ft) ÷ 12 × quantity. Cubic feet = board feet ÷ 12. 1 board foot = 0.00236 m³.

A board foot is 1 inch × 12 inches × 12 inches of wood. Enter up to three board sizes and quantities, add a waste allowance, pick the species for weight, and get total board feet, cubic metres, linear length and cost at your price per board foot.

Results are estimates for planning purposes only. Real-world quantities depend on site conditions, materials and workmanship. Always verify measurements, follow local building codes and confirm quantities with your supplier or a qualified professional before ordering or building.

About the Board Foot Calculator

Hardwood dealers and sawmills do not sell by the linear foot — they sell by the board foot, a volume unit that prices thick wide boards fairly against thin narrow ones. One board foot is a board 1 inch thick, 12 inches wide and 1 foot long. This calculator converts any board dimensions into board feet, totals multi-board cut lists, and prices the job at your per-board-foot rate.

How to use

  1. Enter the board thickness in inches — use the rough-sawn thickness: 4/4 (1 inch), 5/4, 6/4 or 8/4.
  2. Enter the board width in inches and the length in feet.
  3. Enter how many boards of that size you need — the calculator totals the whole cut list.
  4. Enter the price per board foot from your supplier to get the total cost.
  5. Compare species on equal terms: the math is identical, so oak versus walnut is apples to apples.

Understanding your results

Board feet per board is the volume of one piece; total board feet is the whole order — the number the lumberyard invoices against. Total cost is board feet times your rate. If your supplier quotes per thousand board feet (MBF), divide the MBF price by 1,000 first.

How the calculation works

Board feet equal thickness in inches times width in inches times length in feet, divided by 12. A 2×4 that is 8 feet long is (2 × 4 × 8) ÷ 12 = 5.33 board feet — the formula computes volume, with 144 cubic inches per board foot. Total cost is total board feet times price per board foot; MBF is board feet divided by 1,000.

Board Foot Calculator FAQs

About 5.33 board feet. Using nominal dimensions: (2 × 4 × 8) ÷ 12 = 5.33. Note that lumberyards calculate with nominal sizes, not the actual 1.5×3.5 inch dimensions of a finished 2×4. For hardwood bought rough-sawn, use the actual measured thickness instead.
Board feet = thickness (inches) × width (inches) × length (feet) ÷ 12. It is a volume calculation: one board foot equals 144 cubic inches of wood. The formula handles any combination — a thick short slab and a thin long board price out fairly because both are reduced to pure volume.
MBF means one thousand board feet — the M is the Roman numeral for 1,000. Wholesale and mill pricing is often quoted per MBF: USD 4,000 per MBF equals USD 4.00 per board foot. Divide any MBF price by 1,000 before entering it in the calculator as a per-board-foot rate.
Because hardwood comes in random widths and lengths, per-piece pricing would be unfair — a wide 12-foot board contains far more wood than a narrow 6-foot one. The board foot reduces every board to volume, so you pay for the wood you get. Softwood construction lumber, which comes in standard sizes, is the exception sold by the piece.
They are quarters of an inch of rough-sawn thickness: 4/4 is 1 inch, 5/4 is 1.25 inches, 8/4 is 2 inches. After surfacing, 4/4 lumber finishes around 13/16 inch thick. When calculating board feet, use the quarters designation (the rough thickness you pay for), not the surfaced thickness.
Nabil Sharif, founder of CalcDune

Written by

Nabil Sharif

Founder of CalcDune — a free library of 137 online calculators for finance, health and everyday math. Every calculator shows the formula behind its result, so you can see exactly how your numbers are worked out.

More articles by Nabil →

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