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Boards & Panels

Board Foot Calculator

Thickness × width × length ÷ 12 — the hardwood dealer's unit, computed instantly with quarters presets and a cost total at your local price.

Verified against independent hand calculation · sources cited below

Rough-lumber presets:(4/4 = 1″ nominal)

4.00 board feet

Dealers bill on rough (nominal) thickness: a surfaced 13/16″ board still sells as 4/4. Measure width and length as the actual board — most yards round length down to the foot.

The formula, shown

BF = T(in) × W(in) × L(ft) ÷ 12 — or with everything in inches, divide by 144. Worked example: three 8/4 boards, 7-1/4″ wide, 10 ft long: 2 × 7.25 × 10 ÷ 12 = 12.08 BF each, 36.25 BF total. At $8.50/BF that’s about $308.

Buying hardwood without surprises

  • Quarters name rough thickness. 4/4 = 1″, 5/4 = 1-1/4″, 6/4 = 1-1/2″, 8/4 = 2″ — measured before surfacing.
  • Surfaced stock still bills rough. S2S 13/16″ boards sell as 4/4; that’s not a scam, it’s the rule.
  • Yards round length down to the foot, and many round width to the nearest 1/2″ — measure the same way they do.
  • Budget waste. A cut list total is a floor, not a shopping list: add 20–40%.

Frequently asked questions

What exactly is a board foot?

A board foot is 144 cubic inches of lumber — the volume of a board 1″ thick, 12″ wide, and 12″ long. The formula: thickness (in) × width (in) × length (ft) ÷ 12. An 8-foot 4/4 board that’s 6″ wide is exactly 4 board feet.

Why did my 4/4 board measure only 13/16″ thick?

Because board feet are billed on rough thickness, before surfacing. A 4/4 (four-quarter) board starts life 1″ thick at the sawmill; after kiln drying and planing it typically lands at 13/16″. You pay for the 1″ — that’s the convention everywhere hardwood is sold.

How many board feet do I need for my project?

Sum the board feet of your cut list, then add 20–40% for waste — defects, grain matching, tear-out, and mistakes. Furniture makers commonly buy 30% over; figured or rustic lumber with knots deserves 40%+.

Is a board foot the same as a linear foot?

No. A linear foot is just length, ignoring width and thickness. A linear foot of 4/4 × 6″ stock is 0.5 board feet; a linear foot of 8/4 × 10″ stock is 1.67 board feet. Dimensional-lumber stores price linear; hardwood dealers price board feet.

Sources & further reading