How to use the lumber volume calculator
- Use the actual cross-section dimensions, after planing if you want finished volume.
- Enter board length in feet and the number of matching boards.
- Use the cubic volume for storage or mass estimates, or the board-foot conversion for comparison.
The formula
Cubic feet = thickness (in) × width (in) × length (ft) × quantity ÷ 144
Worked example
Twelve boards measuring ¾ × 5½ inches and 8 feet long contain 2.75 cubic feet, equivalent to 33 board feet.
Before you measure and cut
This gives solid wood volume, not the outside volume of a stacked pile. Air gaps between boards are excluded.
If boards are different sizes, calculate each group and add the volumes. Do not average dimensions separately: that can change the total.
Frequently asked questions
Is a cubic foot the same as a board foot?
No. One cubic foot contains 12 board feet. A board foot is 144 cubic inches.
Can I use nominal sizes?
You can, but the result describes nominal volume. Enter actual dimensions to calculate the physical amount of wood.