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. Enter the nominal or actual dimensions. For example, a standard 2×4 that is 8 feet long: Thickness = 2, Width = 4, Length = 8 → (2 × 4 × 8) / 12 = 5.33 board feet.

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.

Board Foot Calculator

Name: Board Foot Calculator
Availability: InStock
Author: Nham Vu

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

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

Summary

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

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: 2026-07-01 · Reviewed by Nham Vu