Board Foot Calculator
Convert lumber dimensions to board feet and price a cut list, with nominal and actual sizes handled correctly.
Your details
A nominal 2×4 actually measures 1.5 × 3.5 inches, but board feet for softwood are conventionally billed on the nominal size.
Cost
Rough-sawn hardwood needs 20-30% to allow for defects, squaring and planing.
This calculator runs entirely on your device. Nothing you enter is uploaded, stored, or sold. How this works
Total board feet
40.00
4.000 bf per piece × 10 pieces
Includes your inputs, the full breakdown, and every row of the table.
Board feet per piece
4.000
With 20% waste
48.00
Estimated cost
$312
Cost per piece
$31.20
- Dimensions
- 1.000" × 6.00" × 8.00 ft
- Board feet per piece
- 4.0000
- Pieces
- 10
- Total board feet
- 40.00
- Waste at 20%
- + 8.00 bf
- Board feet to buy
- 48.00
- At $6.50 per board foot
- $312
- Lineal feet
- 80.0 ft
- Cost per lineal foot
- $3.90
- Surface area one face
- 40.0 sq ft
| Price per bf | Total cost | Per piece | Per lineal ft |
|---|---|---|---|
| $3.00 | $144 | $14 | $2 |
| $4.00 | $192 | $19 | $2 |
| $5.00 | $240 | $24 | $3 |
| $6.00 | $288 | $29 | $4 |
| $8.00 | $384 | $38 | $5 |
| $10.00 | $480 | $48 | $6 |
| $12.00 | $576 | $58 | $7 |
What this means
- One board foot is 144 cubic inches — a piece one inch thick, twelve inches wide and one foot long. Your stock works out at 4.000 board feet per piece.
- At 1.00 inches this is 4/4 stock in hardwood terminology. Remember that 4/4 rough lumber finishes thinner once planed, typically by a quarter inch or so.
- A 20% allowance is appropriate for rough-sawn hardwood, where you lose material to defects, squaring the edges and planing to final thickness.
How the board foot calculation works
A board foot is a volume, not an area, and that distinction causes most of the confusion around it. One board foot is one hundred and forty-four cubic inches — conventionally a board one inch thick, twelve inches wide and one foot long — which means a piece twice as thick contains twice the board feet at the same face dimensions. Hardwood is sold this way because it comes in random widths and lengths, so pricing by volume is the only consistent approach.
Softwood works differently and this trips people up constantly. Dimensional lumber is sold by nominal size, so a 2×4 is billed as though it were two inches by four despite actually measuring an inch and a half by three and a half. The nominal size reflects the rough dimension before drying and planing, and the convention stuck. Board foot calculations for construction lumber use the nominal figure, so a nominal 2×4 counts as two-thirds of a board foot per running foot even though its real volume is considerably less.
Hardwood thickness is quoted in quarters of an inch: 4/4 is one inch, 6/4 is an inch and a half, 8/4 is two. These refer to the rough thickness off the saw, and you lose roughly a quarter inch to planing before you have a usable flat surface. That, plus defects and the need to square edges, is why a twenty to thirty percent waste allowance on rough hardwood is realistic rather than pessimistic.
Frequently asked questions
How do you calculate board feet?
Multiply thickness in inches by width in inches by length in feet, then divide by twelve. Alternatively multiply all three dimensions in inches and divide by one hundred and forty-four. Both give the same answer since a board foot is one hundred and forty-four cubic inches.
Is a board foot the same as a linear foot?
No. A linear foot only measures length and ignores thickness and width entirely. A board foot is a volume, so a 2×12 contains four times the board feet of a 1×6 over the same linear distance.
Do I use nominal or actual dimensions?
For construction softwood, nominal — a 2×4 is billed as two by four even though it measures 1.5 by 3.5. For hardwood, use the actual rough dimensions as measured, since hardwood is sold in random widths and priced on real volume.
What does 4/4 or 8/4 mean?
It is hardwood thickness in quarters of an inch before planing. 4/4 is one inch rough, 8/4 is two inches. Expect to lose about a quarter inch when milling 4/4 down to a flat, usable surface, so plan your finished thickness accordingly.
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Disclaimer. This calculator is provided for general information and educational purposes only and does not constitute financial, tax, legal, medical, or engineering advice. Results are estimates based on the inputs you provide and the assumptions described above. Confirm any figure with a qualified professional before acting on it.