Board Feet Calculator

Estimate board feet for hardwood, rough-sawn, and dimensional lumber. Enter thickness, width, and length with quantity and waste margin for an accurate lumber takeoff.

Lumber Dimensions

Thickness

Width

Length

Quantity

pcs

Waste Margin Allowance10%

0%30%

Live Results

Total Board Feet Required

4.40

Base: 4.00 BF before waste

Per Piece

4.00 BF

Quantity

1 pcs

4.00 BF × 1 pcs = 4.00 BF · Includes 10% waste allowance

How to Use This Calculator

Enter lumber dimensions. Measure thickness and width in inches and length in feet for each piece or uniform batch.
Set quantity. Enter the number of identical pieces. For mixed sizes, calculate each group separately and add totals.
Add waste margin. Use 10% for straight cuts. Increase to 15–20% for planing loss, defects, or complex milling.
Review board feet total. Use the total board feet with waste when requesting lumber yard pricing or placing your order.

Formula & Example

A board foot is the standard unit of measure for rough and hardwood lumber in the United States. One board foot equals the volume of a piece of wood measuring 12 inches long, 12 inches wide, and 1 inch thick — a total of 144 cubic inches. Lumber yards and sawmills price hardwood and rough-sawn stock by the board foot because it accounts for both size and quantity in a single number.

To calculate board feet, multiply the thickness (in inches) by the width (in inches) by the length (in feet), then divide by 12. The division converts the inch-by-inch-by-foot volume into board feet. Multiply by quantity for multiple pieces, then add a waste margin for cuts, defects, and planing loss.

Board Feet (per piece) = (Thickness × Width × Length) ÷ 12

Total Board Feet = Board Feet per piece × Quantity

With Waste = Total × (1 + Waste % ÷ 100)

Rough-Sawn Lumber Thickness Classifications

Classification	Nominal Thickness	Typical Actual Thickness	Common Widths
4/4	1"	13/16" – 1"	4" – 12"
5/4	1-1/4"	1" – 1-1/8"	4" – 12"
6/4	1-1/2"	1-1/4" – 1-1/2"	4" – 12"
8/4	2"	1-3/4" – 2"	4" – 12"

Worked Example

One piece at 1 in × 6 in × 8 ft: (1 × 6 × 8) ÷ 12 = 4 BF. Ten identical pieces = 40 BF base. With 10% waste: 40 × 1.10 = 44 BF total to order.

Frequently Asked Questions

What is a board foot and why do lumber yards use it?▾

A board foot measures lumber volume: one board foot equals a piece 12" × 12" × 1" (144 cubic inches). Lumber yards use board feet because it provides a consistent pricing unit regardless of whether you buy a thin strip or a wide slab — the total volume determines cost. This is especially common for hardwood, rough-sawn, and specialty lumber sold by volume rather than by the stick.

How do I calculate board feet for multiple pieces of lumber?▾

First calculate board feet for one piece: (Thickness × Width × Length) ÷ 12, with thickness and width in inches and length in feet. Then multiply by the number of identical pieces. For mixed sizes, calculate each group separately and add the totals. Example: ten boards at 1" × 6" × 8 ft = 4 BF each × 10 = 40 board feet before waste.

Should I use nominal or actual dimensions when calculating board feet?▾

Use actual measured dimensions for the most accurate takeoff. Rough-sawn lumber is often sold using nominal thickness classifications (4/4, 5/4, 6/4, 8/4), but the actual thickness after drying and surfacing is thinner — for example, 4/4 stock is typically 13/16" to 1" actual. When buying from a lumber yard, confirm whether pricing is based on nominal or actual measure, then enter the dimensions that match how you will be charged.

How much does a board foot of hardwood cost?▾

Hardwood pricing varies widely by species and region — common oak runs $4–$8 per board foot, while exotic species can exceed $15. Always multiply your board foot total by the quoted per-BF price and confirm whether pricing uses nominal or actual dimensions.

What waste margin should I use for hardwood lumber?▾

Start with 10% for straight rips and standard cuts. Bump to 15–20% when planing rough-sawn stock, working around knots, or matching grain patterns on visible surfaces.

Related Tools

Explore more free calculators. Back to home