Board Foot Calculator
Enter thickness, width, length, and quantity to get total board feet, linear feet, and estimated cost for a lumber order.
Updated September 4, 2026 ยท Estimates for planning, not a quote
How to calculate board feet
Board feet is a volume measurement: thickness (in) × width (in) × length (ft) ÷ 12. One board foot is the volume of a board 1 inch thick, 12 inches wide, and 1 foot long. Multiply the board feet per piece by the number of boards for a total order.
Nominal vs. actual lumber dimensions
Board foot pricing uses nominal dimensions, the size lumber is called at the yard, not the smaller size it's actually milled to after drying and planing. A "2x4" doesn't measure 2 by 4 inches; it measures 1.5 by 3.5 inches. Common nominal-to-actual sizes:
- 1x4: actual 0.75 x 3.5 in
- 1x6: actual 0.75 x 5.5 in
- 1x8: actual 0.75 x 7.25 in
- 2x4: actual 1.5 x 3.5 in
- 2x6: actual 1.5 x 5.5 in
- 2x8: actual 1.5 x 7.25 in
- 2x10: actual 1.5 x 9.25 in
- 2x12: actual 1.5 x 11.25 in
Enter the nominal size here, the same numbers printed on the tag at the lumber yard, and this calculator handles the rest. A 2x6 that's 8 feet long comes out to exactly 8 board feet: 2 × 6 × 8 ÷ 12 = 8.
When board feet matters
Board feet is how hardwood and rough-sawn lumber is priced, since boards come in irregular widths and thicknesses that a per-piece or per-linear-foot price can't account for. Dimensional softwood from a home center is usually priced per piece or per linear foot instead, but board feet still tells you how much wood you're actually buying, useful for comparing prices across different sizes.
Method and sources
Where these figures come from: A board foot is 144 cubic inches: nominal thickness in inches times width in inches times length in feet, divided by 12.
Thickness and width are entered as nominal lumber dimensions, the size printed at the yard, because that is how board foot pricing is quoted. The page does not convert to actual milled size.
QuantiYard writes its own formulas and states them in plain language on every page. How these numbers are made covers where the constants come from, how waste factors are chosen, what these calculators deliberately do not do, and how to report an error.
Save the board foot chart
Board feet for six nominal lumber sizes at three common lengths. Save it and you can compare a hardwood price against a softwood one in your head.
Save to PinterestOpens Pinterest with the chart and link ready to go.
Board foot calculator FAQ
How do you calculate board feet?
Multiply thickness in inches by width in inches by length in feet, then divide by 12. A board 1 inch thick, 12 inches wide, and 1 foot long equals one board foot, and every other size scales from that.
Should I use nominal or actual lumber dimensions for board feet?
Use nominal dimensions, the size lumber is sold as. A 2x4 is milled down to 1.5 x 3.5 inches actual, but board foot pricing at the lumber yard is based on the nominal 2 x 4, not the smaller finished size.
How many board feet are in a 2x6 that's 8 feet long?
8 board feet. Using nominal dimensions: 2 inches thick x 6 inches wide x 8 feet long, divided by 12, equals 8.
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