What is a board foot?

A board foot is a unit of volume for lumber. It is defined as the volume of a board that is 1 inch thick, 12 inches wide, and 12 inches long (1 foot).

Does the calculator use nominal or actual dimensions?

The calculator uses the exact dimensions you enter. For hardwoods, you typically use the rough dimensions (eg 4/4 or 8/4). For softwoods, enter the actual measured size if you need precision.

How do you calculate board feet from linear feet?

To convert linear feet to board feet, multiply the linear feet by the (thickness in inches × width in inches) and divide by 12.

Lumber Estimating

Board Foot Calculator

Board feet are the standard volume unit for the lumber industry. Whether you are buying hardwood for fine furniture or estimating framing lumber for a deck, this tool calculates total volume to help you estimate price and weight.

Board Foot Calculator

Convert lumber dimensions into board feet

Quantity

Length

Thickness

Width

Results

Enter dimensions above to calculate

Visualising One Board Foot

One board foot represents 144 cubic inches of wood. It is defined as a board 12 inches wide, 12 inches long (1 foot), and 1 inch thick.

Common Board Foot Counts

Nominal size (in)	Board Feet per Piece
1 × 4 × 8	5.33 BF
1 × 6 × 8	8.00 BF
2 × 4 × 8	10.67 BF
2 × 6 × 10	20.00 BF
2 × 10 × 12	40.00 BF
4 × 4 × 8	21.33 BF

Step-by-Step Formulas

1. Theoretical Volume

Board Feet (BF) = (T" × W" × L') ÷ 12

A board foot is a measurement of lumber volume. One board foot is equivalent to 1" thick × 12" wide × 12" long (144 cubic inches). For any board, multiply thickness(in) × width(in) × length(ft) and divide by 12.

2. Total Project Volume

Total BF = BF per piece × Quantity

Sum the board feet for all pieces in your lumber list. Lumber yards often price hardwood species by the board foot rather than a linear foot price.

3. Waste Allowance

Order BF = Total BF × (1 + Waste%)

When purchasing rough-sawn hardwood, allow 15–25% waste for machining, knots, and defects. For dimensional softwood framing, 5–10% is usually sufficient.

Worked Example

Project: 15 pieces of rough-sawn oak, 5/4 thickness (1.25"), 8" wide, 10' long. Add 20% waste.

BF per piece = (1.25 × 8 × 10) ÷ 12 = 8.33 BF

Total BF = 8.33 × 15 = 124.95 BF

Order total (+20% waste) = 124.95 × 1.20 = 149.94 BF

Lumber yard order: 150 Board Feet

💡 Woodworker's Tip

When buying hardwood, thickness is often stated in quarters. 4/4 ("four-quarters") is 1" thick, while 8/4 is 2" thick. Always calculate board feet based on the rough thickness before you plane the wood down to your finished dimension.

Frequently Asked Questions

What is a board foot?: A unit of volume for lumber equal to 12" × 12" × 1" (144 cubic inches). It is the standard for pricing hardwood lumber.
Does the calculator use nominal or actual dimensions?: It uses the values you enter. Use actual measured dimensions for an accurate project estimate.
What waste factor should I use for hardwood?: Hardwood buyers typically add 20% waste to account for checking, knots, and the thickness lost during surface planing (S2S).