Board Foot Calculator
Convert lumber thickness, width, and length into board feet, and estimate total cost for any number of boards.
Enter the nominal thickness and width in inches, the length in feet or inches, and how many boards you need. Add a price per board foot to also see the total cost.
Step-by-Step Solution
Here's exactly how this answer was calculated, one step at a time.
- 1
Convert all dimensions to inches
Thickness = 1 in, Width = 6 in, Length = 96 in
Length was entered in feet, so it's converted to inches: 8 ft × 12 = 96 in.
- 2
Apply the board foot formula
Board Feet = (T × W × L) ÷ 144 = (1 × 6 × 96) ÷ 144
One board foot equals 144 cubic inches of lumber (a 1 in × 12 in × 12 in board), so multiplying the three dimensions and dividing by 144 gives the board feet in a single board.
- 3
Board feet per board
= 576 ÷ 144 = 4 board feet
This is the volume, in board feet, of one board with the dimensions you entered.
- 4
Multiply by the number of boards
Total Board Feet = 4 × 1 = 4
Multiply the board feet of a single board by how many boards you need.
✓ Final Answer: 4 board feet
Free Online Board Foot Calculator
This board foot calculator converts the thickness, width, and length of lumber into board feet — the standard unit used to price and order hardwood, softwood, and specialty lumber in the US. Enter your board's dimensions and how many boards you need, and the calculator instantly returns the board feet per board, the total board feet, and (if you add a price) the total cost.
Whether you're a woodworker pricing out a project, a contractor ordering framing lumber, or a hobbyist buying rough-sawn hardwood at a mill, this tool gives you an accurate board foot count without doing the math by hand.
What Is a Board Foot?
A board foot is a unit of lumber volume equal to a piece of wood 1 inch thick, 12 inches wide, and 12 inches long — or 144 cubic inches. It's used instead of linear feet because lumber is sold by volume: a 2-inch-thick board contains twice as much wood as a 1-inch-thick board of the same width and length, so pricing by board foot accounts for all three dimensions at once.
Board Foot Formula
The board foot formula multiplies thickness, width, and length (all in inches) and divides by 144:
- Board Feet = (Thickness in inches × Width in inches × Length in inches) ÷ 144
- If length is measured in feet instead: Board Feet = (Thickness in inches × Width in inches × Length in feet) ÷ 12
- Total Board Feet = Board Feet per board × Number of boards
- Total Cost = Total Board Feet × Price per board foot
How to Use This Calculator
Enter the nominal thickness and width of your lumber in inches, then enter the length in either feet or inches using the unit dropdown. Enter how many boards you're buying, and optionally a price per board foot to see the total cost. The calculator updates instantly and shows a full step-by-step breakdown of the math.
Worked Example
Suppose you're buying five boards, each 1 inch thick, 6 inches wide, and 8 feet long. First convert the length to inches: 8 ft × 12 = 96 in. Then apply the formula: (1 × 6 × 96) ÷ 144 = 4 board feet per board. Multiply by 5 boards to get 20 total board feet. At $4.00 per board foot, the total cost would be 20 × $4.00 = $80.00.
Where Board Feet Are Used
Board foot pricing is standard across several areas of woodworking and construction:
- Hardwood and lumber yards price rough-sawn and specialty wood by the board foot rather than by linear foot.
- Woodworkers and furniture makers use board feet to estimate material cost before starting a project.
- Sawmills use board feet to measure log yield and finished lumber output.
- Contractors sometimes convert framing lumber quantities to board feet for bulk material quotes.
Frequently Asked Questions
What is a board foot?
A board foot is a unit of lumber volume equal to a board 1 inch thick, 12 inches wide, and 12 inches long (144 cubic inches). It's the standard way lumber is priced and sold in the US.
How do you calculate board feet?
Multiply the thickness, width, and length of the board, all in inches, and divide by 144: Board Feet = (Thickness × Width × Length in inches) ÷ 144. If length is in feet, divide by 12 instead.
Is a board foot the same as a linear foot?
No. A linear foot only measures length, ignoring thickness and width. A board foot accounts for all three dimensions, so it reflects the actual volume of wood in a piece of lumber.
Does board foot use actual or nominal lumber dimensions?
Board foot pricing traditionally uses nominal (rough-sawn) dimensions rather than the smaller actual dimensions of surfaced/planed lumber. Use the nominal thickness and width listed by your supplier for the most accurate board foot count.
How do I find the total cost of lumber from board feet?
Multiply the total board feet by the price per board foot quoted by your supplier. This calculator does that automatically when you enter a price.