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Board Feet Calculator

Thickness and width in inches, length in feet, to board feet.

Also known as board feet calculator · decking board feet · lumber board feet

Quick answer

With the default inputs: Thickness 2 in · Width 6 in · Length 8 ft etc.Total board feet 160.0 BF

Use your own dimensions ↓

Inputs

in
in
ft
pcs
$

Result

Total board feet
160.0BF
Board feet each8.00BF
Total linear feet160ft
Pieces20bars
Nominal section2 × 6in
Volume13.33ft³
Cost at entered price0.00$
How this is worked out

Board feet = thickness(in) x width(in) x length(ft) ÷ 12, so a 2x6x8 is 2 x 6 x 8 / 12 = 8 BF. Note this uses nominal sizes, not actual: a North American 2x6 measures 1.5 x 5.5 in, but board feet and pricing have always run on nominal. That is convention, not an error - calculate on actual sizes and you will come out about 20% under the invoice. Decking is usually bought by the linear foot while framing is priced by the board foot, so check which basis your supplier quotes before comparing. An 8 ft 2x6 is 8 BF, about $9.60 at $1.20/BF.

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Formula

BF = T(in) × W(in) × L(ft) ÷ 12nominal sizes
Total BF = BF each × pieces
Linear feet = length × pieceshow decking is sold
Volume (ft³) = BF × 144 ÷ 17281 BF = 144 in³
Twenty 2x6x8s: 2 x 6 x 8 / 12 = 8 BF each, 160 BF total, 160 linear feet, about 13.3 ft³ of actual timber, roughly $192 at $1.20/BF.

How to work it out

  1. Check whether the quote is per board foot or per linear foot - decking is usually linear, framing is board feet.
  2. BF = thickness(in) x width(in) x length(ft) ÷ 12, using nominal sizes throughout.
  3. Multiply by pieces for total board feet and work out total linear feet at the same time.
  4. Add waste: 10% framing, 15% trim, more for mitred work.
  5. Estimate cost from a price per board foot, but remember retail is priced per piece, not at an average.

Where it goes wrong

Material and cost

Softwood framing runs about USD 0.55-1.20 per board foot and moves a lot with the market (it tripled in 2021). Finish grade is 1.50-3.50 and hardwood such as oak or walnut 4-12 per board foot. Retail sells by the piece: an 8 ft 2x4 is 3-6 and an 8 ft 2x6 is 6-12, with bulk orders cheaper.

On site

Basis

FAQ

What is the difference between board feet and linear feet?
Linear feet counts length only; board feet includes the cross-section. So 100 linear feet of 2x4 and of 2x10 differ 2.5-fold in board feet. Decking and trim bought by run are priced per linear foot, while framing lumber, timber and hardwood price per board foot - cross-sections vary too much to quote on length alone.
Why nominal rather than actual dimensions?
It is a century-old convention: a 2x4 actually measures 1.5 x 3.5 in, yet board feet, list price and structural tables all use nominal 2x4. Rough-sawn stock really was 2x4 originally, and planing and drying shrank it while the pricing system stayed put. Use nominal for buying, and actual only when you are calculating finished sizes for furniture or cabinetry.
How much waste should I add?
10% for framing, 15% for trim and mitred work, and 20-30% for hardwood where grain and defects have to be worked around. Mind the lengths too: nominal 8 ft stock usually measures slightly over but prices at 8 ft, which is normal. For trim, count how many usable pieces come out of each length rather than dividing total run by piece length, or the joints will not land where you need them.

Cite this page

Use this format in reports, method statements or coursework. The link is permanent.

Building Calculator. Board Feet Calculator. 2026-10-25. https://jianzhujisuan.com/en/deck-board-feet

Results are estimating aids only and are not a design basis. Construction and final accounts must follow the drawings, the applicable standards and an approved method statement. Anything affecting structural safety, shoring or falsework must be checked by a suitably qualified engineer.