Lumber Volume Calculator

Board Foot Calculator for Lumber Volume and Cost Estimates

Calculate board feet fast, estimate lumber cost, and review the formulas and examples you need before pricing hardwood, softwood, or rough cut boards.

Jump to calculator View formula guide
  • Works with inches, feet, millimeters, centimeters, and meters.
  • Estimates total cost from price per board foot.
  • Supports pinned values and shareable URLs for repeat estimates.

Core Tool

Use the calculator

Enter your board size, number of pieces, and optional price per board foot. The calculator updates instantly as you type.

Board Foot Calculator

Free online lumber volume calculator for woodworking, milling, and estimating jobs.

in
Thickness of a single board. Rough lumber is often listed in quarter sizes such as 4/4 or 8/4.
in
Actual board width. For surfaced boards, use the measured width rather than nominal size.
ft
Use total board length in the unit your lumber yard or shop uses.
board feet
Total lumber volume in board feet.

Lumber Cost Calculator

$ / board foot
Multiply this rate by total board feet to estimate your lumber cost.
$
Total cost for lumber purchase.

Definition

What is a board foot?

A board foot is a volume measurement used by lumber yards, sawmills, cabinet shops, and woodworkers. One board foot equals a piece of wood that is 1 inch thick, 12 inches wide, and 12 inches long. Because it measures volume, it is more useful than square footage when thickness changes from one board to another.

That is why hardwood pricing is often quoted as price per board foot. It lets suppliers charge correctly for boards that have different thicknesses, widths, and lengths.

Formula

Board foot formula

The standard formula is simple when all dimensions are in inches:

Board Feet = (Thickness x Width x Length x Pieces) / 144

If your length is measured in feet, you can also use this shortcut:

Board Feet = (Thickness in inches x Width in inches x Length in feet x Pieces) / 12

Read the full formula guide

Conversion

Square feet to board feet

You cannot convert square feet to board feet without knowing board thickness. Surface area only tells you coverage. Board feet needs thickness because it measures total lumber volume.

Once thickness is known, use this rule:

Board Feet = Square Feet x Thickness in inches

Open the conversion guide

Worked Examples

Sample board foot calculations

These examples cover common lumber estimating situations for shops, mills, and jobsite takeoffs.

Board size Pieces Board feet At $4.25 per BF
1 x 12 x 10 ft 1 10.00 $42.50
2 x 6 x 8 ft 8 64.00 $272.00
8/4 x 6 x 10 ft 3 30.00 $127.50
5/4 x 8 x 12 ft 6 60.00 $255.00

Estimating

How to estimate lumber cost accurately

1. Measure actual size

Nominal dimensions can differ from actual surfaced dimensions. Use the real thickness and width when cost needs to be precise.

2. Add waste factor

For rough lumber, trim loss, defects, and matching grain can all increase required footage. Many buyers add 10% to 20% depending on the project.

3. Separate by species or grade

Maple, walnut, oak, and softwood framing stock often carry very different prices per board foot. Quote them separately before totaling.

FAQ

Board foot questions

How many board feet are in a 2 x 4 x 8?

Using actual dimensions in the formula gives about 5.33 board feet if you use full 2 x 4 sizing, or less if you use surfaced actual dimensions.

Why is board foot different from square foot?

Square foot measures area. Board foot measures volume. Lumber pricing needs thickness, so square footage alone is not enough.

Can this tool calculate cost too?

Yes. Enter the price per board foot and the calculator multiplies it by total board feet to estimate total lumber cost.

Should I use nominal or actual dimensions?

Use actual dimensions whenever you need a closer estimate for purchase orders, cabinet parts, or surfaced lumber.

Related Guides

These supporting pages target the next most common board foot questions and send internal links back to the main tool.

How to Calculate Board Feet

Step-by-step instructions, worked examples, and common estimating mistakes.

Board Foot Formula

Understand the exact equation, shortcuts, and when to divide by 12 or 144.

Square Feet to Board Feet

Learn when you can convert directly and when thickness changes the answer.

Price Per Board Foot

Estimate total cost from board footage and compare pricing scenarios.