Board Foot Calculator
Work out board feet for lumber from thickness, width, length and quantity, for up to three board sizes, with the cost.
Board 1
Board 2 (optional)
Board 3 (optional)
Results
| Item | Value |
|---|
Boards
| Board | Size | Board feet |
|---|
Quick Answer
One board foot is 12 × 12 × 1 inches, or 144 cubic inches. To find board feet, multiply thickness (in) × width (in) × length (ft) and divide by 12. Ten 2×6 boards that are 8 ft long are 2 × 6 × 8 ÷ 12 × 10 = 80 board feet.
Embed this calculator
Adjust the size if needed, then copy the code below into your page or blog. The calculator will load in an iframe and stay updated automatically.
Table of Contents
How This Board Foot Calculator Works
Hardwood lumber is often priced by the board foot, a unit of volume. Enter the size and number of each board, up to three sizes, and the calculator gives the total board feet and an estimated cost.
Quick explanation: board feet = thickness (in) × width (in) × length (ft) ÷ 12.
- 1 board foot: a board 1 inch thick, 12 inches wide and 1 foot long.
- Several sizes: fill in Board 2 and Board 3 if needed.
- Waste: add extra for cuts, knots and defects.
Core Formulas
- Length in feet: T × W × L ÷ 12
- Length in inches: T × W × L ÷ 144
- Total: board feet × quantity
- Cost: total board feet × price per board foot
Worked Example
You need four oak boards, 1 inch thick, 8 inches wide and 10 ft long, at $6 per board foot.
- One board = 1 × 8 × 10 ÷ 12 = 6.67 board feet
- Four boards = 26.67 board feet
- Cost = 26.67 × $6 = $160.00
Nominal and Actual Sizes
- Softwood: a 2×4 is about 1.5 × 3.5 inches after planing.
- Hardwood: thickness is often given in quarters, such as 4/4 (1 inch) or 8/4 (2 inches).
- Pricing: suppliers usually price by nominal size, so use that unless told otherwise.
Frequently Asked Questions
Multiply thickness in inches by width in inches by length in feet, then divide by 12.
2 × 4 × 8 ÷ 12 = 5.33 board feet, using nominal size.
A volume of 144 cubic inches, the same as a board 1 inch thick, 12 inches wide and 1 foot long.
There are 12 board feet in a cubic foot.
Use the size your supplier prices by. Most use nominal size for board feet.
References & Sources
| Source | Used For | Link |
|---|---|---|
| Wikipedia, Board foot | Definition of the board foot. | https://en.wikipedia.org/wiki/Board_foot |
| Wikipedia, Lumber | Nominal and actual lumber sizes. | https://en.wikipedia.org/wiki/Lumber |