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Board Foot Calculator

Lumber Volume and Price by the Board Foot

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How the Board Foot Calculator works

This board foot calculator works out the volume of lumber in board feet, the unit hardwood and much timber is priced in across North America. Enter the thickness and width in inches and the length in feet, or all three in millimetres, the number of pieces and your price per board foot, and it returns the board feet, the volume in cubic metres and cubic feet and the cost.

A board foot is a piece 1 inch thick, 12 inches wide and 12 inches long: 144 cubic inches, or 1/12 of a cubic foot. One cubic metre holds about 424 board feet. Hardwood yards quote prices per board foot so that boards of any size can be compared fairly.

How the board foot calculator works

The formula is board feet = thickness (in) × width (in) × length (ft) ÷ 12. For example, a 2 × 6 that is 8 ft long is 2 × 6 × 8 ÷ 12 = 8 board feet, and ten of them are 80 board feet; at 3.00 a board foot that is 240.00. A second example in metric: a 50 × 150 mm board 2.4 m long is 0.018 m³, or 7.63 board feet.

Hardwood is measured by its rough thickness in quarters of an inch: 4/4 is 1 in, 8/4 is 2 in. Use the rough size, not the planed size, because that is what the yard charges for. Softwood dimensional lumber is sold by nominal size (a 2 × 4 is really 1.5 × 3.5 in), and board feet are worked out on the nominal size too.

To see how many boards you need for a project, work out the board feet in the finished parts and add 20–30% for defects, grain matching and saw waste.

Board feet in one piece of common nominal lumber sizes, by length

Nominal size 6 ft 8 ft 10 ft 12 ft 16 ft
1 × 2 1 1.33333 1.66667 2 2.66667
1 × 3 1.5 2 2.5 3 4
1 × 4 2 2.66667 3.33333 4 5.33333
1 × 6 3 4 5 6 8
1 × 8 4 5.33333 6.66667 8 10.6667
1 × 10 5 6.66667 8.33333 10 13.3333
1 × 12 6 8 10 12 16
2 × 2 2 2.66667 3.33333 4 5.33333
2 × 3 3 4 5 6 8
2 × 4 4 5.33333 6.66667 8 10.6667
2 × 6 6 8 10 12 16
2 × 8 8 10.6667 13.3333 16 21.3333
2 × 10 10 13.3333 16.6667 20 26.6667
2 × 12 12 16 20 24 32
3 × 6 9 12 15 18 24
4 × 4 8 10.6667 13.3333 16 21.3333
4 × 6 12 16 20 24 32
4 × 8 16 21.3333 26.6667 32 42.6667
6 × 6 18 24 30 36 48
6 × 8 24 32 40 48 64
8 × 8 32 42.6667 53.3333 64 85.3333

FAQ

How do you calculate board feet?

Multiply the thickness in inches by the width in inches by the length in feet, then divide by 12. A 1 × 8 board 10 ft long is 1 × 8 × 10 ÷ 12 = 6.67 board feet. If the length is in inches, divide by 144 instead of 12.

How many board feet are in a cubic metre?

There are about 423.8 board feet in one cubic metre, and 12 board feet in one cubic foot. So a cubic metre of timber is 35.3 cubic feet, and one board foot is about 0.00236 m³, or 2.36 litres of wood.

Do you use nominal or actual size for board feet?

For softwood dimensional lumber, board feet are normally calculated on the nominal size, so a 2 × 4 counts as 2 by 4 inches. For hardwood sold rough, use the rough thickness in quarters and the actual measured width of each board.

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