Lumber Calculator (Board Feet)

Adds up the board feet in a list of lumber, estimates the cost from a price per board foot, and shows the actual size of nominal lumber such as a 2×4. Use it when buying wood priced by the board foot or checking what a nominal size really measures.

How to use

1. For each line, choose a "Nominal size" (or "Custom size" to type the thickness and width), then enter "Length (ft)" and "Pieces".
2. Press "Add another line" for each further size. "Total board feet" and "Total linear feet" update as you type.
3. Enter a "Price per board foot" to see the "Estimated cost".
4. Under "Linear feet and board feet", pick a size and type either value to convert it to the other.

How it works

• Board feet = thickness (in) × width (in) × length (ft) ÷ 12. One board foot is 144 cubic inches, for example 1 in × 12 in × 1 ft.
• By default board feet use the nominal size, the way softwood is usually priced. Switch on "Use actual (dressed) size" to use the measured size instead.
• The size table lists the minimum dressed sizes of dry softwood from the American Softwood Lumber Standard, DOC PS 20-20 (January 2020). Green lumber is slightly larger.
• Your list is saved in this browser.

Questions and answers

How many board feet are in a 2x4x8?

2 × 4 × 8 ÷ 12 = 5.33 board feet, using the nominal size. Ten of them are 53.3 board feet.

What are the actual dimensions of a 2x4?

A dry 2×4 is 1-1/2 in × 3-1/2 in (38 × 89 mm). A 2×6 is 1-1/2 in × 5-1/2 in, and a 4×4 is 3-1/2 in square.

How do I convert linear feet to board feet?

Multiply the linear feet by thickness × width in inches and divide by 12. For a 2×6, 100 linear feet are 100 board feet; for a 1×6, they are 50 board feet.

How do I enter hardwood thickness like 5/4?

Choose "Custom size" and type the thickness as a fraction such as 5/4 or 8/4. Lengths can also be typed as 8' or 96".