Board feet from actual board dimensions: volume and purchase quantity.
How do board feet differ from board count and linear feet?
Use the units required by the formula
One board foot is 144 cubic inches: a 1 in × 12 in × 12 in volume. With thickness and width in inches and length in feet, board feet = thickness × width × length × count / 12. The Board Foot Calculator normalises supplied physical dimensions before displaying volume.
Do not silently replace the supplier’s billing convention
A product name is not a measurement record. If the quote uses nominal or rough dimensions while your calculation uses measured finished dimensions, label both bases. A physical volume calculation should not be represented as the supplier’s invoice quantity without that check.
Separate volume from piece fit
The five boards in the example have the same total volume as other collections of different lengths. A required 9 ft piece cannot be obtained as a continuous piece from an 8 ft board merely because enough board feet were purchased. Use a stock cut plan for fit and keep volume for the selected billing basis.
Price the basis actually quoted
At an illustrative 4 currency units per board foot, the 20-board-foot order costs 80 before other charges. At 16 per whole board, five boards also cost 80 in this particular example. That numerical equality is incidental; compare both quote formats using their actual board dimensions and whole-stock requirements.
Use the matching calculator
Use this decision sequence
- Record the physical thickness and width on a named measurement basis.
- Record each board length and quantity.
- Calculate volume, then convert to board feet.
- Confirm whether the supplier bills on those dimensions or another quoted basis.
Keep the quantities distinct
| Quantity or assumption | How to use it |
|---|---|
| Board feet | A unit of timber volume. |
| Linear feet | A length total without thickness or width. |
| Board count | Whole physical stock items. |
Worked comparison
Five illustrative boards measuring 1 in × 6 in × 8 ft contain 1 × 6 × 8 × 5 / 12 = 20 board feet. Their combined length is 40 linear feet. Neither figure alone proves the pieces in a cut list will fit.
Check before using the estimate
Nominal product names and measured physical dimensions can have different billing bases.
All dimensions, product properties, prices and specifications in this example are illustrative arithmetic inputs. Use the values from your measured plan, selected product data sheet and supplier quote. This guide does not choose construction specifications or certify safety.
Calculation and scope checked 2026-10-13. Methods and scope.