Board Foot Calculator.
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Browse allWhat Is a Board Foot Calculator?
A board foot calculator converts lumber dimensions into board feet — the standard volume unit used when buying and selling hardwood, softwood, and milling stock. Enter thickness and width in inches, length in feet or inches, and the number of pieces.
One board foot equals a piece 1″ thick × 12″ wide × 1′ long (144 cubic inches).
How to Use This Calculator
- Enter thickness in inches (use actual size, not nominal — e.g. 1.5 for a 2×4).
- Enter width in inches.
- Choose length unit — feet or inches — and enter the length.
- Enter quantity — how many identical pieces you have.
- Review board feet, cubic feet, and cubic inches instantly.
Board Foot Formula
T = thickness in inches, W = width in inches, L = length in feet, Qty = number of identical pieces. One board foot = 1″ × 12″ × 1′ (144 cubic inches). Convert inch-lengths to feet by dividing by 12.
Worked Example
You have one piece of lumber: 1″ thick × 6″ wide × 8′ long (a common 1×6 board).
Board feet = (1 × 6 × 8) / 12 × 1 = 4.000 bf
Cubic feet = 4 / 12 = 0.333 ft³
Cubic inches = 1 × 6 × 96 = 576 in³
At $8 per board foot, this single board would cost about $32 before tax and delivery.
Frequently Asked Questions
How do you calculate board feet?
Board Feet = (Thickness × Width × Length in feet) / 12 × Quantity. All thickness and width values are in inches; length must be in feet (divide inches by 12).
Should I use nominal or actual lumber dimensions?
Always use actual measured dimensions. A nominal 2×4 is about 1.5″ × 3.5″ after planing — using 2″ × 4″ overstates board feet by roughly 78%.
How do I estimate lumber cost from board feet?
Multiply total board feet by your lumberyard's price per board foot. Example: 24 bf × $8/bf = $192 before tax and delivery.
How many board feet in a 2×4×8?
Using actual size (1.5″ × 3.5″ × 8′): (1.5 × 3.5 × 8) / 12 = 3.5 bf per piece. Ten pieces = 35 bf total.
How many cubic feet are in a board foot?
One board foot = 1/12 cubic foot (≈ 0.0833 ft³). Divide board feet by 12 to get cubic feet.
Why is lumber sold by board feet instead of cubic feet?
Board feet standardize pricing across different board sizes — a thin wide board and a thick narrow board can both be compared per bf at the lumberyard.
Can I enter length in inches?
Yes. Toggle to inches and the calculator converts to feet before applying the formula.
How do I calculate board feet for multiple pieces?
Calculate board feet for one piece, then multiply by quantity — or enter quantity directly in this calculator. Example: 4 bf per board × 12 boards = 48 bf.
Getting board feet right saves money on every lumber order. Use this free calculator before you buy, and pair it with our cubic feet calculator when you need volume in different units.