What is a board foot?

A board foot is a unit of lumber volume equal to a piece 1 inch thick, 12 inches wide, and 12 inches long — or 144 cubic inches. It is the standard unit used to price and sell hardwood and rough-sawn lumber in North America.

What is the board foot formula?

Board Feet = (Thickness in inches × Width in inches × Length in feet) / 12. Equivalently, if all three dimensions are in inches: (T × W × L) / 144.

Does this work for dimensional lumber like 2×4s?

Yes. Use nominal sizes for dimensional softwood, as lumber yards do: a 2×4 that is 8 feet long is (2 × 4 × 8) / 12 = 5.33 board feet even though it measures 1.5 × 3.5 inches. For rough-sawn hardwood, use the measured thickness and width.

How do I calculate board feet for multiple pieces?

Click "+ Add Piece" for each distinct size. Set the Quantity field to cover multiples of the same dimension. The calculator multiplies board feet per piece by the quantity and sums all rows.

Why is lumber sold by board feet instead of linear feet?

Board feet account for both cross-section size and length, giving a true volume measure. Linear feet only measure length, so a 2×4 and a 2×8 of the same length contain very different amounts of wood. Board feet make pricing fair regardless of dimension.

What if my lumber length is in inches?

Convert inches to feet by dividing by 12 before entering. For example, 96 inches = 8 feet. Alternatively, use the all-inches formula: (T × W × L_inches) / 144.

What do 4/4 and 8/4 mean for hardwood?

Rough hardwood thickness is sold in quarters of an inch: 4/4 is 1 inch, 5/4 is 1.25, 6/4 is 1.5 and 8/4 is 2 inches. Enter the quarter value in inches, so 8/4 goes in as 2.

How do I price lumber by the board foot?

Multiply total board feet by the price per board foot. For example, 20 board feet at $6.50 per board foot costs $130. Enter the price here and the calculator does it for all pieces.

What is MBF and how do I convert a price per MBF?

MBF means one thousand board feet, the unit sawmills and wholesalers often quote. Divide the MBF price by 1,000 to get the price per board foot: $850 per MBF is $0.85 per board foot. Enter that per-board-foot price here.

Board Foot Calculator

Calculate board feet of lumber from thickness, width, and length across multiple pieces, with optional total cost estimate.

Board feet = thickness in inches × width in inches × length in feet ÷ 12.

Lumber Pieces

Qty

Thickness (in)

Width (in)

Length (ft)

Board Feet

Total Board Feet 0.000

Optional Cost Estimate

Price per Board Foot ($)

Estimated Cost

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Formula: Board Feet = (Thickness × Width × Length) / 12 | Thickness & Width in inches, Length in feet

Quick answer

Board feet = thickness in inches × width in inches × length in feet ÷ 12. One board foot is 144 cubic inches, such as a board 1 inch thick, 12 inches wide and 1 foot long. Lumber yards count dimensional lumber by nominal size, so a 2x4 counts as 2 × 4 even though it measures 1.5 × 3.5 inches.

Examples

Board	Board feet
1 x 6, 8 ft	4.00
2 x 4, 8 ft	5.33
1 x 8, 10 ft	6.67
2 x 6, 10 ft	10.00
2 x 10, 12 ft	20.00
8/4 hardwood, 6 in wide, 8 ft	8.00

Add your boards and price.

Summary

The Board Foot Calculator helps woodworkers, contractors, and lumber buyers quickly determine the volume of lumber in board feet. Enter dimensions for one or more pieces — thickness, width, and length — along with quantities, and the tool instantly totals board footage. Optionally add a price per board foot to estimate material cost. All calculations run client-side in your browser.

How it works

Add one or more lumber pieces using the "+ Add Piece" button.
Enter the quantity, thickness (inches), width (inches), and length (feet) for each piece.
The calculator applies the formula: Board Feet = (Thickness × Width × Length) / 12 per piece.
Totals update instantly as you type.
Optionally enter a price per board foot to see the estimated material cost.
Use the trash icon to remove any row you no longer need.

Use cases

Estimating lumber costs before purchasing wood for a furniture or carpentry project.
Calculating board footage when buying rough-sawn timber at a sawmill.
Determining material volume for decking, framing, or flooring projects.
Comparing lumber quotes that are priced per board foot.
Teaching students or apprentices the board foot measurement system.

Frequently Asked Questions

Last updated: 2026-05-29 · Reviewed by Nham Vu