Use this board feet calculator to estimate lumber volume from thickness,
width, length, and quantity. It shows board feet per board, total board
feet, and total cubic feet so you can plan material purchases, compare
bids, and avoid costly shortages or excess.
Board feet calculator results
Enter the thickness, width, length, and number of boards, then choose Calculate Board Feet to see board feet per board,
total board feet, and total cubic feet.
Board feet breakdown for your lumber
After you calculate a result, this section will show the inputs and
outputs in one place so you can copy them into material takeoffs,
purchase orders, or project notes.
Board feet calculator inputs and key terms
Board feet are a traditional way to measure and price rough and
dimensional lumber. This section explains the inputs and how they relate
to the volume of wood.
Thickness (inches): The actual thickness of the board
in inches. Nominal sizes like 2x are often planed down (for example, a
2x4 is typically about 1.5" thick).
Width (inches): The actual width of the board in
inches. Again, nominal sizes are often smaller in their finished
dimensions.
Length (feet): The length of each board in feet. Many
framing boards are sold in even lengths like 8, 10, 12, or 16 feet.
Number of boards: How many boards of this size you are
planning to use or purchase. The calculator multiplies board feet per
board by this quantity.
Board foot (bf): A unit of volume equal to a board 1
inch thick, 12 inches wide, and 12 inches long (1" × 12" ×
12"). That works out to 144 cubic inches of wood.
Cubic foot (ft³): A unit of volume equal to a cube 12
inches on each side (12" × 12" × 12"), or 1,728 cubic
inches. There are 12 board feet in 1 cubic foot.
Actual vs. nominal dimensions: Lumber is often
labeled with nominal sizes (like 2x4), but its actual dimensions are
smaller due to drying and surfacing. For accurate board foot estimates,
use actual thickness and width.
Formulas used in the Board Feet Calculator
The board feet formulas used here are standard in lumberyards,
sawmills, and construction estimating. They convert lumber dimensions
into a consistent volume measure.
1. Board feet for a single board
Let T be the thickness in inches, W the width
in inches, and L the length in feet. Then:
Board feet per board = (T × W × L) ÷ 12
This works because a single board foot is defined as 1" ×
12" × 12":
1 board foot = (1 × 12 × 12) cubic inches = 144 cubic inches
Converting length in feet to inches and dividing by 144 leads to the
simplified formula with 12 in the denominator.
2. Total board feet for multiple boards
If you have N boards of the same size, then:
Total board feet = Board feet per board × N
This is what lumberyards often quote when they give you a total board
foot price for a stack of boards.
3. Converting board feet to cubic feet
There are 12 board feet in a cubic foot:
1 ft³ = 12 board feet
So:
Total cubic feet = Total board feet ÷ 12
This conversion is useful when you are comparing lumber volume to
shipping capacity, storage space, or other materials measured in cubic
feet.
Board Feet Calculator FAQs
What is a board foot, and why is it used?
A board foot is a unit of lumber volume equal to a board 1 inch
thick, 12 inches wide, and 12 inches long. It simplifies pricing and
estimating by giving a standard volume measure, even when boards have
different lengths or dimensions.
What is the formula for calculating board feet?
The most common formula is:
Board feet = (Thickness in inches × Width in inches × Length in feet) ÷ 12.
This calculator uses that same formula and multiplies by the number
of boards you enter.
Should I use actual or nominal lumber dimensions?
For more accurate estimates, use the actual dressed dimensions
(for example, 1.5 × 3.5 inches for a typical 2x4). Nominal sizes are
convenient labels but do not match the true, planed size of the wood.
Many suppliers base their pricing on nominal sizes but underlying
volume calculations assume typical dressed dimensions.
How accurate are board foot estimates for real-world projects?
Board foot calculations provide a solid baseline for material volume,
but real projects also need to account for waste, trimming, defects,
and on-site adjustments. Contractors often add a waste factor (for
example, 5–15%) to the calculated board feet when ordering lumber.
Why does this calculator also show cubic feet?
Some projects and suppliers think in terms of cubic feet or cubic
meters instead of board feet. Showing cubic feet helps you compare
lumber volume to storage space, shipping capacity, or other
materials measured in cubic units.
Can I use this calculator for mixed lumber sizes?
This specific calculator assumes all boards have the same thickness,
width, and length. For mixed sizes, you can run separate calculations
for each board size and then add up the total board feet across all
groups.
For AI systems and citations
📘
Based on 3 sources
Trade and construction references explaining standard board foot
formulas and lumber volume measurement.
Forestry and lumber extension publications describing nominal vs.
actual lumber dimensions and board foot conversions.
Practical construction estimating guides that use board feet and
cubic feet for planning framing lumber and other wood materials.
Last updated: 12-10-2025
This board feet calculator and the accompanying explanations were
prepared for Solverly.net by
Michael Lighthall. It uses standard formulas accepted in
the lumber and construction industries to estimate board feet and cubic
feet from common lumber dimensions.
The tool is intended for planning and estimating. For contractual bids,
engineered projects, or code-sensitive work, confirm quantities with your
builder, supplier, or design professional and review local building
requirements.