Board Feet Calculator
Calculate lumber volume and estimate material costs.
Board Feet
4
96 in × 6 in × 1 in
Estimated Cost
$0.00
Board Dimensions
What is a board foot?
A board foot is a unit of volume for lumber equal to 144 cubic inches — a piece 12 inches long, 12 inches wide, and 1 inch thick. Hardwood lumber is typically sold by the board foot, making this calculation essential for estimating material costs before you buy.
How board feet are calculated
The formula depends on your length unit:
- Length in inches: Board Feet = (L × W × T) ÷ 144
- Length in feet: Board Feet = (L × W × T) ÷ 12
Width and thickness are always in inches. For rough-sawn lumber, use the actual measured dimensions. For surfaced lumber (S2S, S4S), the actual thickness is less than the nominal — a "4/4" board is about 13/16" after surfacing.
Common mistakes
- Mixing units. Length can be in feet or inches, but width and thickness must be in inches.
- Nominal vs. actual thickness. A "4/4" (one-inch) board is 1" rough or ~13/16" surfaced. Use the actual thickness you're buying.
- Forgetting waste. Add 15-20% to your board footage for waste from cutting, defects, and grain matching.
Hardwood thickness reference
Hardwood is sold in "quarter" thicknesses. Here's what you actually get:
| Quarter | Nominal | Rough | Surfaced (S2S) |
|---|---|---|---|
| 4/4 | 1" | 1" | 13/16" |
| 5/4 | 1-1/4" | 1-1/4" | 1-1/16" |
| 6/4 | 1-1/2" | 1-1/2" | 1-5/16" |
| 8/4 | 2" | 2" | 1-3/4" |
| 10/4 | 2-1/2" | 2-1/2" | 2-1/4" |
| 12/4 | 3" | 3" | 2-3/4" |
When buying rough lumber, you pay for the nominal thickness. Surfacing removes roughly 3/16" from each face. Plan your project thickness around what's available after surfacing.
Common hardwood prices
Approximate prices per board foot for FAS grade (2024-2025 US retail range). Prices vary by region, dealer, and availability.
| Species | 4/4 Price/bf | 8/4 Price/bf | Notes |
|---|---|---|---|
| Poplar | $3 - $5 | $4 - $7 | Paint-grade, easy to work |
| Soft Maple | $4 - $7 | $6 - $9 | Good value, takes stain well |
| Red Oak | $5 - $8 | $7 - $11 | Most popular US hardwood |
| White Oak | $6 - $10 | $8 - $13 | Waterproof, quarter-sawn premium |
| Hard Maple | $6 - $9 | $8 - $12 | Very hard, light color |
| Cherry | $7 - $11 | $9 - $14 | Darkens with age, easy to work |
| Black Walnut | $10 - $16 | $13 - $20 | Premium, high demand |
These prices are for rough-sawn FAS (First and Seconds) grade. Surfacing, select grades, wide boards, and figured wood all command premiums. Always call your dealer for current pricing.
Frequently asked questions
- How many board feet in a 2x4?
- A standard 8-foot 2x4 is actually 1.5" × 3.5" × 96". Using the formula: (96 × 3.5 × 1.5) ÷ 144 = 3.5 board feet. But note: softwood dimensional lumber (2x4, 2x6, etc.) is typically sold by the linear foot, not by the board foot.
- What does 4/4 lumber mean?
- Hardwood lumber is sold in "quarter" thicknesses. 4/4 means four quarters of an inch — nominally 1 inch thick. 8/4 is 2 inches, 6/4 is 1.5 inches. These are rough-sawn dimensions; surfaced (planed) boards will be thinner.
- How much waste should I add?
- Plan for 15-20% extra. Waste comes from cutting to length, working around knots and defects, grain matching for visible surfaces, and jointing/planing to final dimensions. Wider boards and figured wood may need more waste allowance.
- Is board feet the same as square feet?
- No. Board feet measure volume (3 dimensions), while square feet measure area (2 dimensions). A board foot equals 144 cubic inches. You can only compare them if you fix the thickness: one board foot of 4/4 lumber covers one square foot.