How do you calculate board feet?

Board feet = thickness (inches) × width (inches) × length (feet) ÷ 12. If your length is in inches, divide by 144 instead. One board foot is a volume of 144 cubic inches — a piece 1 inch thick, 12 inches wide and 12 inches long.

What does 4/4, 5/4 or 8/4 lumber mean?

Hardwood thickness is quoted in quarters of an inch: 4/4 is 1 inch, 5/4 is 1.25 inches, 6/4 is 1.5 inches, and 8/4 is 2 inches. Surfaced thickness can be smaller. Confirm your supplier's measurement and billing basis.

How many board feet are in a cubic meter?

One cubic meter equals approximately 423.78 board feet. This calculator shows both units for every board and for your whole cut list.

Board Foot Calculator

Q: Do I use nominal or actual dimensions for board feet?

For a purchase estimate, use the dimensions your supplier bills, which may be rough or nominal rather than surfaced dimensions. For physical volume, use actual measurements. BoardsCalc calculates the dimensions entered; it does not convert actual sizes to nominal sizes.

Measure a board, type it in — fractions welcome (3/4, 1 1/2). Get board feet and cost instantly, then stack up a cut list and print it for the yard.

New to buying lumber? The lumber buying guide walks through priced examples, nominal versus actual sizes, and what the waste allowance does not cover.

One board

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Width in

Length

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Fractions work in any field: 3/4 · 1 1/2 · 1-1/2. For buying lumber, confirm the sizes your supplier bills.

Price per board foot (optional) Name this board (for the list)

Board feet

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Per board

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Lumber math, straight

The board foot formula

board feet = thickness (in) × width (in) × length (ft) ÷ 12
…or with length in inches: T × W × L ÷ 144

One board foot is 144 cubic inches of rough lumber — a 1″ × 12″ × 12″ piece. It's a volume, not an area, which is why a 2″-thick board costs twice the footage of a 1″ board of the same face size.

4/4, 5/4, 8/4 — the quarters system

Hardwood thickness is quoted in quarter-inches at the sawmill: 4/4 ("four-quarter") = 1″, 5/4 = 1¼″, 6/4 = 1½″, 8/4 = 2″, 12/4 = 3″. The chips enter these thicknesses for you. Surfaced boards can be thinner; confirm your supplier's measurement and billing basis rather than assuming every yard uses the same rule.

Do I use nominal or actual dimensions for board feet?

For a purchase estimate, enter the dimensions your supplier bills, which may be rough or nominal sizes. For physical volume, use actual measurements. BoardsCalc calculates exactly the dimensions you enter; it does not convert actual sizes into nominal sizes.

Why add waste?

The default 15% is an editable planning assumption, not a guarantee of yield. The waste field scales net footage and priced cost by 1 + waste%. The Buy count rounds up extra pieces separately for each board type. Those whole pieces may cost more than the proportional cost estimate; see the worked project before ordering.

Board feet ↔ cubic meters

1 m³ ≈ 423.78 board feet (1 BF = 0.00236 m³). Flip the unit toggle to enter dimensions in centimeters — the calculator shows both units either way, handy for imported and European-spec stock.

Is anything I type uploaded?

Calculations run locally. Where browser storage is available, your cut list and settings are saved on this device and restored on a later visit; closing the tab does not erase them. Clear empties the saved list. Print, CSV and JSON let you keep a separate copy. A share link contains the project in its URL fragment: anyone you send it to can read it. See the privacy policy.

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