Board feet to buy
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Shop estimate. Measure your stock and cut a test on scrap.
How to use it
- Measure thickness and width in the unit you are paying for. A 4/4 rough board is entered as 1 inch even when a corner is thin. A surfaced board is entered as the thickness you measured.
- Enter length in feet, or switch to millimetres and enter metres. A suffix such as ft, in, or mm overrides the field.
- Set the quantity and add a row for each different size.
- Add a waste percent if you want defects and offcuts covered. Ten to twenty percent is a common furniture allowance. It is not a measurement of your pile.
- Read board feet, cubic metres, and, if you typed a price, the extended cost. The cost is your number times the volume.
The formula
Board feet = thickness (in) × width (in) × length (in) × quantity ÷ 144
- 144. Cubic inches in one board foot. The same volume is thickness × width × length in feet ÷ 12.
- Waste. Scales the volume. Fifteen percent on 4 board feet is 4.6 board feet to buy.
- m³. One board foot is 144 cubic inches, about 0.00236 cubic metres.
Worked example
A rough board 1 inch thick, 6 inches wide, and 8 feet (96 inches) long is 4 board feet. Add 15% for waste and defects and the buy is 4.6 board feet. At a price you type of 9 per board foot, the line is 41.40 in your currency. That price is multiplication, not a quote from a yard.
A dressed 2×4 at 1½ by 3½ inches, 8 feet long, is 3.5 board feet. The nominal 2 by 4 by 8 figure is larger, and it is the wrong volume for the stick in your hand. Dimension lumber is usually sold by the piece. Use dressed thickness and width when you are counting wood you already have.
What it will not decide
- It does not grade the board or deduct wane, checks, or sapwood.
- It does not lay clear cuttings out on the board. Identical crosscuts belong on the kerf page. Rectangles on a panel belong on the sheet page.
- A board foot is volume. It says nothing about how flat the board is.
Questions
Is an eight-foot 2×4 five and a third board feet?
Only if you multiply the nominal 2 by 4. The dressed stick is about 1½ by 3½ inches, which is 3.5 board feet at eight feet. Yards sell dimension lumber by the piece. Use the nominal-size page for the dressed measurement, then come back if you need the volume of wood you actually have.
Why show cubic metres next to board feet?
Canadian hardwood dealers often still price by the board foot, while a metric quote may arrive in cubic metres. Both numbers are the same volume. Compare them before you compare the price.
Does waste make the board longer?
No. Waste multiplies the volume. It is a buying allowance, not a change to the length you measured.