Board Foot Calculator
Calculate board feet and lumber cost for one or more boards. Hardwood pricing, project estimates, and shopping lists in seconds. No sign-up needed.
| # | Description | Thick (in) | Width (in) | Length (ft) | Qty | $/BF | BF each | Total BF | Cost |
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Total board feet
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Estimated cost
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Line items
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Avg $/BF
Formula
Board feet = (thickness × width × length) ÷ 12.
Use nominal inches for thickness and width, and length in feet.
Methodology
Board feet explained.
The board-foot formula
BF = (T × W × L) ÷ 12, where T is thickness in inches, W is width in inches, and L is length in feet. One board foot is 144 cubic inches of wood.
When to use nominal vs. actual dimensions
At home improvement stores, use the nominal dimensions (2×6, 4×4) — that's how lumber is listed on the price tag. At hardwood dealers and sawmills, measure the actual thickness and width of each slab or plank. The formula is the same either way.
Waste factor
This calculator computes exact board feet from your inputs. In practice, add 10–15% for cuts and defects when ordering hardwood, and 10–20% for dimensional lumber depending on the pattern (see the deck calculator for pattern-based waste factors).
FAQ
Frequently asked questions.
What is a board foot?
A board foot is a unit of wood volume equal to a piece 1 inch thick, 12 inches wide, and 12 inches long (144 cubic inches). It is the standard unit for pricing hardwood and dimensional lumber at sawmills and hardwood dealers.
How do I calculate board feet?
Board feet = (thickness in inches × width in inches × length in feet) ÷ 12. For example, a 2×6×12 ft board: (2 × 6 × 12) ÷ 12 = 12 board feet.
Do I use nominal or actual dimensions?
Use the nominal (stated) dimensions for lumber bought at a big-box store — a 2×6 is listed as 2×6, so use those. For rough-sawn hardwood from a sawmill, use the actual measured thickness and width. The board-foot formula works the same way; just be consistent.
Why is hardwood priced in board feet?
Hardwood slabs, planks, and timbers vary in width and thickness, so a linear foot measurement is misleading. Board feet capture the actual volume of wood, making pricing fair regardless of the plank's dimensions.
What does $/BF mean?
Dollars per board foot — the standard pricing unit at hardwood dealers. Oak typically runs $4–$8/BF; walnut $10–$20/BF. Your dealer will quote you a price per board foot; enter it here to get a total cost estimate.
Can I enter multiple lumber species or projects?
Yes — this calculator supports multiple rows. Add one row per board or per species, enter the price per board foot if you have it, and the calculator sums everything up at the bottom.