How this calculation works
One geometric board foot is 144 cubic inches. Sum each batch’s dimensional volume in that unit, and show the equivalent solid volume in cubic metres. The calculation follows the supplied dimensions, not a grading or commercial tally rule.
BF = thickness(in) × width(in) × length(ft) × pieces / 12A worked example
Ten pieces entered as 2 inches × 6 inches × 12 feet each contain 120 geometric board feet, equivalent to 0.28316846592 m³.
Good to know
A geometric material-planning estimate from the entered measurements. Check actual product dimensions and the project layout. No structural suitability, installation specification, local requirements, labor, tax or pricing is determined. Decimal input lists allow up to 6 places and at most 100 entries/rows, each no greater than 1,000,000. No nominal/dressed-size lookup, log scaling, grading, drying shrinkage, product pricing or commercial tally rules. Use the dimensions appropriate to the task and label their basis.
Reference: Penn State Extension: definition and calculation of board feet (opens in a new tab) ↗
Board feet measure volume, not the number of boards
One geometric board foot is 144 cubic inches: a piece one inch thick, twelve inches wide and twelve inches long. The formula uses thickness and width in inches but length in feet, which is why the product is divided by twelve.
A piece entered as 2 inches by 6 inches by 12 feet contains 12 geometric board feet. Ten identical pieces total 120 BF. A count of ten boards alone would not describe their material volume.
Separate rows allow different sizes to be combined while retaining each batch’s contribution. The displayed solid-volume conversion uses the same dimensional volume, not a new estimate of usable finished yield.
Label the dimensions behind a tally
A nominal lumber label and a measured dressed size can differ. This calculator uses exactly the dimensions you supply and does not infer one from the other. A geometric result from measured dimensions is not automatically a commercial grading tally.
The volume converter can express solid volume in additional units. Board-foot volume also differs from a log-scaling rule, which estimates potential sawn yield and depends on its own assumptions.
If you are planning cuts from uniform stock lengths, the skirting cut planner addresses allocation and offcuts rather than cubic volume. A correct total volume does not guarantee that the available pieces can produce every required finished length.
A few questions, answered
Does it convert a nominal two-by-four to its dressed size?
No. Enter the dimensions appropriate to your task; this tool does not apply nominal-size tables.
What does the piece count mean?
A positive whole number of identical pieces in that row. Use another row for a different dimensional batch.
Is this a timber valuation?
No. It totals geometric volume. Grade, usable yield, moisture, defects, price and commercial measurement rules are separate.