Board Foot Calculator

The board foot calculator multiplies thickness in inches, width in inches and length in feet, then divides by 12. It returns board feet per board and total board feet for your quantity, plus an estimated cost when you enter a price per board foot.

Last reviewed September 2026Method & sources Report an error

Total Board Feet

40.00 bd ft

Breakdown
Total Board Feet	40.00 bd ft
Board Feet per Board	4.00 bd ft
Estimated Cost

How to Calculate Board Foot

A board foot is a volume unit equal to a board 1 in. thick, 12 in. wide, and 12 in. long (144 cubic inches). For a board of any thickness, width, and length, board feet is `(thickness in inches × width in inches × length in feet) ÷ 12`. You divide by 12 rather than 144 because length is already given in feet, not inches. Multiplying by the number of boards gives the total. Multiplying that by a price per board foot (the standard way hardwood and specialty lumber is priced) gives an estimated cost.

Example: 10 boards, each 1 in. thick × 6 in. wide × 8 ft long

10 boards, each 1 in. thick × 6 in. wide × 8 ft long: 1. Board feet per board: (1 × 6 × 8) ÷ 12 = 48 ÷ 12 = 4 bd ft 2. Total board feet: 4 × 10 = 40 bd ft At $8 per board foot, this order would cost 40 × $8 = $320.

Board Foot: Compare Scenarios

Scenario	Total Board Feet	Board Feet per Board
Small project (5 boards, 1x6x8)	20.00 bd ft	4.00 bd ft
Medium order (10 boards, 1x6x8)	40.00 bd ft	4.00 bd ft
Large order (50 boards, 1x6x8)	200.00 bd ft	4.00 bd ft

What Is Board Foot?

A board foot calculator converts a board's dimensions into board feet. Board feet is the volume-based unit hardwood, exotic, and specialty lumber is typically priced and sold by. Dimensional construction lumber, like a 2x4, is usually priced per linear foot or per piece regardless of thickness.

Board Foot: Pros and Cons

Pros

Directly applies the standard board foot formula used throughout the hardwood and specialty lumber trade
Handles any thickness, width, and length combination rather than assuming one standard dimension
Gives both per-board and total board feet, useful for comparing prices between different board sizes

Cons

Doesn't account for a rough-sawn board's actual thickness, which typically runs slightly more than its nominal size. A rough "4/4" board is closer to 1-1/16 in. than a true 1 in. Use the board's actual measured thickness for precise pricing
Assumes a single board size. An order with multiple different board dimensions needs each size calculated separately and the totals added
Doesn't include waste for defects, knots, or cutting. Hardwood is sometimes sold with a defect allowance already factored into the price, so check with your specific supplier

Board Foot: What a Pro Checks

Measure actual thickness, not nominal, before pricing an order. Rough-sawn "4/4" lumber usually runs closer to 1-1/16 in. than a true 1 in., which changes your board footage more than it looks like it should.
Calculate each board size separately and add the totals if your order mixes dimensions. This calculator assumes one uniform thickness, width, and length per run.
Ask your supplier whether their price already builds in a defect allowance for knots and cutting waste. Some hardwood pricing bakes this in, so you may not need to buy extra on top of it.

Frequently Asked Questions

What is a board foot?

A board foot is a unit of lumber volume equal to a piece 1 in. thick, 12 in. wide, and 12 in. long (144 cubic inches). It applies regardless of the actual shape of the board being measured, as long as the total volume matches.

How do you calculate board feet?

Multiply thickness (inches) × width (inches) × length (feet), then divide by 12. A board 1 in. thick, 6 in. wide, and 8 ft long is (1 × 6 × 8) ÷ 12 = 4 board feet.

Why is hardwood priced by the board foot instead of by the piece?

Hardwood boards commonly come in varying widths and thicknesses, unlike standardized dimensional construction lumber. Pricing by volume rather than by linear foot or by piece gives a consistent, fair way to compare cost across boards of different sizes.

Is a 2x4 priced by the board foot?

Typically not. Standard dimensional construction lumber like a 2x4 or 2x6 is usually priced per linear foot or per piece, since it comes in standardized sizes. Board foot pricing is mainly used for hardwood, rough-sawn, and specialty lumber where sizes vary more.

Does board foot account for actual vs. nominal lumber size?

This calculator uses whatever thickness and width you enter, so for the most accurate result, measure the board's actual dimensions rather than its nominal size. A nominal 1 in. rough board is often slightly thicker than a true 1 in. Surfaced/planed lumber is often slightly thinner.

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