How to Calculate Board Feet
The one formula you need
board feet = (thickness in x width in x length in) / 144
Everything else is a shortcut of this.
Step by step
- Measure thickness and width in inches and length in inches.
- Multiply the three together to get cubic inches.
- Divide by 144.
If your length is in feet, multiply thickness by width by length in feet and divide by 12 instead. Same answer, one less conversion.
For a whole order
Do each board size on its own, multiply by how many of that board you need, then add the groups together. That is exactly what the tally calculator on the home page automates.
Metric sizes
If your stock is in millimeters or centimeters, convert to inches first (1 inch = 25.4 mm = 2.54 cm), or just use the calculator and switch the unit. The board foot itself stays an imperial unit.
Common mistakes
- Using actual planed size instead of nominal size
- Forgetting to multiply by quantity
- Mixing feet and inches in the same formula
- Skipping a waste allowance and coming up short
Frequently asked questions
- What is the board foot formula?
- Thickness times width times length in inches, divided by 144. Or thickness times width times length in feet, divided by 12.
- How do I calculate board feet for a whole project?
- Figure each board size separately, multiply by quantity, and add the totals. The tally calculator does this for a full cut list.
- How do I add waste?
- Multiply your total board feet by 1 plus the waste percentage. For 15 percent waste, multiply by 1.15.