Board Feet to Cubic Feet Calculator

How do you convert board feet to cubic feet?

Cubic feet = board feet ÷ 12. The factor comes straight out of the definition, not out of a rounding habit: a board foot is 1″ × 12″ × 12″, which is 144 cubic inches, and a cubic foot is 12″ × 12″ × 12″, which is 1,728 cubic inches. 1,728 ÷ 144 = 12, so twelve board feet fill exactly one cubic foot — no species, no moisture content, no thickness in the formula.

Read the other direction, board feet = cubic feet × 12, and the single unit nobody asks about twice: 1 board foot = 0.0833 cubic feet (that is 1 ÷ 12, or 144 in³). If you were looking for what one board foot is in volume terms, that is the whole answer — see what a board foot is for the picture of it.

The constants behind every row, worth writing on the back of a tape measure: 12 BF = 1 ft³, 1 ft³ = 0.028316846592 m³, 1 m³ = 423.776 BF, 1 yd³ = 324 BF, 1 MBF = 83.333 ft³ = 2.3597 m³.

This arithmetic gets searched under several names that all mean the same division: a lumber volume calculator, a cubic feet of wood calculator, a way to calculate cubic feet of wood from a footage tally, measuring timber volume, a timber calculator in cubic feet. Boards, timbers and squared stock all take ÷12; the only thing that genuinely changes is how the volume was measured in the first place — a round log is scaled differently before it is ever board feet, which is why logs have their own log calculator.

What is cft, and when do you need it instead of board feet?

Cft is just cubic feet written the way paperwork writes it — you will see "100 cft" on an import manifest, a freight quote, a quantity surveyor's take-off or a timber-estimate spreadsheet, and it means the same 100 ft³. The vocabulary splits by trade: board feet (bf, bd ft, BF) is what a lumberyard sells you, cft is what a shipper, estimator or scales-and-load clerk uses, and MBF (or M board feet, where M is the Roman thousand) is how mills and wholesalers quote big lots.

The bridge is one multiplication each way: 100 cft × 12 = 1,200 board feet, and 1,200 BF ÷ 12 = 100 cft. So when a broker quotes "40 cft of white oak" he is quoting 480 BF, and when your tally says 480 BF the crate is 40 ft³ of solid wood before stacking gaps. Nobody converts to cft out of preference — you get pushed there when the number stops being a price and starts being a space or a weight: a container, a trailer, a kiln charge, a dumpster.

Billed cubic feet vs the wood that actually arrives

This is the part the plain divide-by-twelve answers hide, and it is where money or freight gets misjudged. Board feet are tallied on nominal size; your pile is real size. A 2×6 is billed as 12 in² of cross-section but measures 1.5″ × 5.5″ = 8.25 in², so the actual wood in it is only 8.25 ÷ 12 = 0.6875 of what the ticket counts. Rough-sawn 4/4 hardwood runs the opposite way — it leaves the saw at 1⅛″ while being tallied at 1″ — so the pile is 12.5% larger than the bill.

The rule is one line: actual ft³ per 100 billed BF = 8.333 × (actual area ÷ nominal area), and billed BF per 1 actual ft³ = 12 ÷ (actual area ÷ nominal area). Worked out for the sizes people actually haul:

The last row is the check on my arithmetic: 10.67 billed board feet per cubic foot of rough 4/4 is the figure rough-sawn dealers publish in their own tally guides (the number circulates on woodweb.com among hardwood dealers), and it falls straight out of 12 ÷ 1.125. The 2× dimensions come from the nominal-versus-actual size chart; the 1⅛″ rough thickness is the hardwood thickness call convention.

Two numbers to keep from this table. Surfaced framing lumber delivers only about 66% (2×4) to 70% (2×12) of the volume you paid for — which is fine for pricing and terrible for guessing a trailer's cubic content. Rough hardwood delivers about 112%. If a hauler asks how many cubic feet your order is, answer with the actual column, not 100 ÷ 12.

Worked example: 350 board feet of rough 4/4, and 2,000 board feet of 2×6

350 BF of rough 4/4 walnut. Billed volume = 350 ÷ 12 = 29.17 ft³. Actual wood = 29.17 × 1.125 = 32.81 ft³ — the pile is bigger than the invoice, which is why a rough tally looks generous on the board-foot line and heavy on the drying rack.

2,000 BF of 2×6 framing stock. Billed volume = 2,000 ÷ 12 = 166.67 ft³. Actual = 166.67 × 0.6875 = 114.58 ft³. A trailer rated at 120 ft³ of solid wood takes this load; rated at 150 ft³ of nominal volume, it does not. Same invoice, two different answers, and only one of them keeps you from a second trip.

Price per board foot, per MBF, per cubic foot, per cubic metre

Quotes arrive in four different currencies of volume and people compare them badly. Because 12 BF = 1 ft³ and 1,000 BF = 1 MBF, the chain is mechanical. Take a mill run quoted at $1,400 per MBF:

Use whichever row matches the paper in front of you, and never compare a $/m³ import quote against a $/BF yard quote without moving one of them first — the metric number always looks enormous because a cubic metre is 423.776 board feet. The lumber cost calculator runs the same chain against your own species and waste factor.

Cubic feet to pounds: the ×12 density bridge

The same factor 12 converts weight units, which is the fastest way to sanity-check any species table you find — including ours. Pounds per board foot × 12 = pounds per cubic foot.

The lb/ft³ column is the ×12 identity; the kg/m³ column is that figure × 16.018, rounded. So if a density chart tells you white oak is 48 lb per cubic foot and a lumber table tells you 4.0 lb per board foot, they are the same fact stated twice — and where two published lists disagree, the gap is rounding or moisture content, never a different wood. For hauling, drying and floor-loading maths use the board foot weight calculator, which does the moisture adjustment on the same numbers.

Which unit should you be using?

• Buying solid lumber → board feet. It is what the yard bills, and it is thickness-aware, which a square foot is not.
• Covering a surface (decking, flooring, shelving, sheathing) → square feet, via the board feet to square feet converter.
• Counting sticks or lengths → linear feet, with the board feet to linear feet converter.
• Freight, containers, kiln charges, burn or dump volume → cubic feet (cft) and cubic yards — this page.
• Import, export, metric contracts → cubic metres, at 423.776 BF per m³.
• Standing trees and logs → a log scale, not board feet: the log board foot calculator uses Doyle, International ¼″ and Scribner, which deliberately discount for what a saw can get out of a round stick.

And before you commit any of these to a purchase, the volume you buy is not the volume you finish with — the waste factor guide covers cut-offs and bad ends, which is the usual reason a clean 25 ft³ order turns into a 20 ft³ project.