Board Foot Calculator
Enter each board's size and count. Totals update as you type and are saved in this browser.
How board feet are calculated
A board foot is a volume of wood 1 inch thick, 12 inches wide and 12 inches long (144 cubic inches).
board feet = thickness (in) × width (in) × length (in) ÷ 144
Example: an 8/4 board, 6" wide and 8' long is 2 × 6 × 96 ÷ 144 = 8 board feet.
What does 4/4 or 8/4 mean?
Hardwood thickness is sold in quarters of an inch. 4/4 ("four quarter") is 1", 5/4 is 1¼", 6/4 is 1½" and 8/4 is 2". Type it just like that in the thickness box. Board feet are normally calculated on the rough (nominal) thickness.
Nominal vs. actual size
Dimensional lumber is named by its nominal size, the size of the rough board before it was dried and planed. The board you take home is smaller. A 2×4 is actually 1½" × 3½".
| Nominal | Actual (in) | Actual (mm) | Board feet per 8' (nominal) |
|---|---|---|---|
| 1×4 | ¾ × 3½ | 19 × 89 | 2.67 |
| 2×4 | 1½ × 3½ | 38 × 89 | 5.33 |
| 2×6 | 1½ × 5½ | 38 × 140 | 8.00 |
| 4×4 | 3½ × 3½ | 89 × 89 | 10.67 |
Lumberyards usually count board feet on the nominal size, so enter 2 × 4 to match their numbers. Enter the actual size if you want the real volume of wood.
How much extra to buy
Some wood is always lost to knots, checks, twist and saw cuts. Add 10% to your total for straight, clear stock and simple projects, and up to 20% for rough lumber, matched grain or many short parts. For example, a 40 board-foot project calls for 44 to 48 board feet.
Units
Choose Inches × Inches × Feet (how lumber yards usually quote), Inches for everything, orMillimetres. Fractions like 3/4 or 1 1/2 work in inch fields.
Frequently asked questions
How many board feet are in a 2×4×8?
Using the nominal size, 2 × 4 × 96 ÷ 144 = 5.33 board feet, which is how lumberyards usually count it. Using the actual size of 1½" × 3½", the same board holds 3.5 board feet of wood.
Should I enter nominal or actual sizes?
Enter the sizes your seller uses, so your total matches their price. Dimensional softwood like 2×4s is normally counted on nominal size. Hardwood is counted on its rough thickness (4/4, 8/4 and so on) with the width and length you measure.
How do board feet convert to cubic feet or cubic metres?
12 board feet make 1 cubic foot, and 1 cubic metre is about 424 board feet.
What is the difference between board feet and linear feet?
Linear feet measure length only, whatever the board’s thickness and width. Some yards price dimensional lumber and trim per linear foot. One linear foot of a board holds thickness × width ÷ 12 board feet, so a foot of 2×6 is 1 board foot.
Are my boards saved?
Yes. Your boards and price are saved in this browser so they are still there next time. They are never sent to a server. Use Clear all to start over.