Board Foot Calculator
Our Board Foot Calculator gives you a simple way to convert lumber dimensions into board feet and estimate the total amount of wood you need. Enter the thickness, width, length, and number of boards to get an instant result.
Board Foot Calculator
Calculate board feet, total lumber volume, and estimated lumber cost from your board dimensions.
Use inches for thickness and width, and feet for length.
Thickness × Width × Length ÷ 12
My lumber list
| Size | Length | Qty | BF / board | Total BF | Cost | |
|---|---|---|---|---|---|---|
| Your lumber list is empty. Add a board above to build an estimate. | ||||||
A board foot represents 144 cubic inches of lumber volume.
Thickness × width × length ÷ 12 when dimensions use inches, inches, and feet.
Enter a price per board foot to estimate the material cost of your lumber.
What Is a Board Foot?
A board foot is a unit used to measure the volume of lumber.
One board foot represents a piece of wood measuring:
1 inch thick × 12 inches wide × 1 foot long
The board-foot measurement is particularly useful when comparing lumber with different dimensions because it converts the physical size of the boards into a common volume measurement.
For example:
- 1 × 12 × 1 ft = 1 board foot
- 2 × 6 × 10 ft = 10 board feet
- 2 × 8 × 10 ft = 13.33 board feet
- 2 × 12 × 10 ft = 20 board feet
Construction calculators commonly use the same inch × inch × feet format for board-foot calculations.
How to Calculate Board Feet
The standard formula is:
Board Feet = Thickness (inches) × Width (inches) × Length (feet) ÷ 12
If you are calculating several identical boards:
Total Board Feet = Board Feet per Board × Number of Boards
Example
Suppose you have ten boards measuring:
- Thickness = 2 inches
- Width = 8 inches
- Length = 10 feet
First calculate one board:
2 × 8 × 10 ÷ 12 = 13.33 board feet
Then multiply by the number of boards:
13.33 × 10 = 133.33 board feet
So the lumber order contains approximately 133.33 board feet.
Board Foot Examples
| Lumber size | Length | Board feet |
|---|---|---|
| 1 × 6 | 8 ft | 4 BF |
| 1 × 8 | 10 ft | 6.67 BF |
| 2 × 4 | 8 ft | 5.33 BF |
| 2 × 6 | 10 ft | 10 BF |
| 2 × 8 | 10 ft | 13.33 BF |
| 2 × 10 | 12 ft | 20 BF |
| 2 × 12 | 12 ft | 24 BF |
| 4 × 4 | 8 ft | 10.67 BF |
These calculations use the nominal dimensions shown in the table. When purchasing lumber, remember that the actual dimensions of finished boards can be smaller than their nominal size.
Board Feet vs. Square Feet
Board feet and square feet measure different things.
Square feet measure surface area.
Board feet measure lumber volume based on thickness, width, and length.
For example, a 1-inch-thick board measuring 12 inches wide and 10 feet long contains 10 board feet.
A thicker board with exactly the same width and length contains more board feet because it contains more wood.
This distinction matters when estimating hardwood or other lumber sold using board-foot pricing.
Board Foot Cost Calculator
If lumber is priced by the board foot, you can estimate the material cost with:
Lumber Cost = Total Board Feet × Price per Board Foot
Example
If your project requires:
85 board feet
and the lumber costs:
$8 per board foot
then:
85 × $8 = $680
Your estimated lumber cost would therefore be $680.
Keep in mind that actual lumber prices can vary by species, grade, thickness, supplier, location, and whether the wood is rough-sawn or surfaced.
Some standard dimensional lumber is instead sold by the piece, so a board-foot calculation isn’t necessarily the same thing as the price you see on a retail lumber shelf.
Board Foot Calculator for Hardwood
Board feet are especially useful when working with hardwood because boards can have very different dimensions.
Imagine two pieces of hardwood:
Board A: 1 × 8 × 8 ft
Board B: 2 × 4 × 8 ft
They have different shapes, but both contain:
5.33 board feet
This makes board feet useful for comparing lumber quantities without having to compare each board’s dimensions separately.
For rough or irregular lumber, however, the way a supplier measures the boards may differ from a simple calculation based on nominal dimensions. Always check the seller’s measurement and pricing method before purchasing expensive lumber.
How to Calculate Board Feet From Multiple Boards
When your lumber order contains different sizes, don’t put all the dimensions into one calculation.
Instead:
Step 1
Calculate the board feet of the first lumber size.
Step 2
Multiply by the number of boards of that size.
Step 3
Repeat for each different size.
Step 4
Add the results.
For example:
4 boards of 2 × 6 × 8 ft
2 × 6 × 8 ÷ 12 × 4 = 32 BF
And:
3 boards of 2 × 8 × 10 ft
2 × 8 × 10 ÷ 12 × 3 = 40 BF
Total:
32 + 40 = 72 board feet
This approach is particularly helpful when preparing a mixed lumber order.
When Should You Use a Board Foot Calculator?
A board-foot calculation can be useful when you need to:
- Estimate hardwood quantities
- Compare lumber orders
- Calculate the volume of boards
- Estimate lumber costs
- Price woodworking materials
- Estimate furniture material
- Compare boards with different dimensions
- Prepare a lumber shopping list
- Check a supplier’s board-foot calculation
- Estimate material for woodworking projects
It can also be useful for contractors, carpenters, woodworkers, DIY builders, furniture makers, and anyone buying lumber by volume.