Board Foot Calculator
Calculate board feet and total lumber cost for multiple boards at once. Supports nominal and actual dimensions, wood species price presets, and live updates. Faster and more powerful than Omni Calculator.
🪵 Board Foot Calculator
Use nominal dimensions (e.g. 2×4 = 2 in × 4 in)
— off = actual dimensions
#
Thickness (in)
Width (in)
Length (ft)
Qty
BF
🌲 Wood Species Preset (price per board foot)
$
%
Total Board Feet
—
BF
With Waste Factor
—
BF (+10%)
Total Cost
—
incl. waste
—Board Feet
—Cubic Inches
—Cubic Feet
—Cubic Meters
📋 Table of contents
What is a board foot?
A board foot (BF or BDF) is a unit of lumber volume used in the United States and Canada to price and purchase wood. One board foot equals the volume of a piece of lumber that is 1 foot long × 1 foot wide × 1 inch thick.
1 board foot =
144 cubic inches
= 1/12 cubic foot
= 0.00236 cubic meters
= 2.36 liters
Dimensions: 12 in × 12 in × 1 in = 144 in³
Board footage is different from square footage — it measures volume, not area. This means thickness matters. A 1-inch thick board and a 2-inch thick board with the same footprint contain different amounts of wood, so they cost different amounts per board foot.
When is board footage used? Hardwood lumber (oak, maple, walnut, cherry) is almost always sold by the board foot. Softwood lumber for construction (pine, spruce, fir in 2×4, 2×6 sizes) is often sold by the lineal foot or piece, but is sometimes priced by BF for custom or mill orders.
Board foot formula
Standard formula (length in feet):
BF = Thickness (in) × Width (in) × Length (ft) ÷ 12
Alternative (all dimensions in inches):
BF = Thickness (in) × Width (in) × Length (in) ÷ 144
Example — 1 board, 1.5 in × 8 in × 10 ft:
BF = 1.5 × 8 × 10 ÷ 12 = 10 BF
Example — 5 boards, 1 in × 6 in × 8 ft each:
BF per board = 1 × 6 × 8 ÷ 12 = 4 BF
Total = 5 × 4 = 20 BF
Cost calculation:
Total cost = Total BF × Price per BF
Example: 20 BF × $6.00/BF = $120.00
Nominal vs actual lumber dimensions
When you buy a "2×4" from a lumber yard, you are not getting a board that is 2 inches thick and 4 inches wide. The nominal size is the rough-cut size before drying and planing. The actual size is smaller.
| Nominal Size | Actual Size | BF per 8ft (nominal) | BF per 8ft (actual) |
|---|---|---|---|
| 1 × 2 | ¾ × 1½ in | 1.33 | 0.75 |
| 1 × 4 | ¾ × 3½ in | 2.67 | 1.75 |
| 1 × 6 | ¾ × 5½ in | 4.00 | 2.75 |
| 1 × 8 | ¾ × 7¼ in | 5.33 | 3.63 |
| 1 × 10 | ¾ × 9¼ in | 6.67 | 4.63 |
| 1 × 12 | ¾ × 11¼ in | 8.00 | 5.63 |
| 2 × 4 | 1½ × 3½ in | 5.33 | 3.50 |
| 2 × 6 | 1½ × 5½ in | 8.00 | 5.50 |
| 2 × 8 | 1½ × 7¼ in | 10.67 | 7.25 |
| 2 × 10 | 1½ × 9¼ in | 13.33 | 9.25 |
| 2 × 12 | 1½ × 11¼ in | 16.00 | 11.25 |
| 4 × 4 | 3½ × 3½ in | 10.67 | 8.17 |
Hardwood vs softwood convention: Hardwoods (oak, walnut, maple) are typically sold using actual thickness in quarters of an inch (4/4 = 1 in, 8/4 = 2 in, 12/4 = 3 in). Softwood construction lumber uses nominal sizes. When using this calculator, confirm which sizing convention your supplier uses and toggle accordingly.
Common lumber sizes & board feet
Here are board feet per piece for the most common lumber dimensions at standard lengths:
| Board Size (nominal) | 8 ft | 10 ft | 12 ft | 16 ft |
|---|---|---|---|---|
| 1×4 | 2.67 | 3.33 | 4.00 | 5.33 |
| 1×6 | 4.00 | 5.00 | 6.00 | 8.00 |
| 1×8 | 5.33 | 6.67 | 8.00 | 10.67 |
| 1×10 | 6.67 | 8.33 | 10.00 | 13.33 |
| 1×12 | 8.00 | 10.00 | 12.00 | 16.00 |
| 2×4 | 5.33 | 6.67 | 8.00 | 10.67 |
| 2×6 | 8.00 | 10.00 | 12.00 | 16.00 |
| 2×8 | 10.67 | 13.33 | 16.00 | 21.33 |
| 2×10 | 13.33 | 16.67 | 20.00 | 26.67 |
| 2×12 | 16.00 | 20.00 | 24.00 | 32.00 |
| 4×4 | 10.67 | 13.33 | 16.00 | 21.33 |
| 6×6 | 24.00 | 30.00 | 36.00 | 48.00 |
Wood species prices per board foot (2025)
Hardwood prices vary significantly by species, grade, and region. These are approximate retail prices:
| Species | Type | $/BF (approx.) | Common Uses |
|---|---|---|---|
| Pine (Eastern White) | Softwood | $1.25–$2.00 | Framing, shelving, trim |
| Spruce | Softwood | $1.50–$2.50 | Framing, construction |
| Douglas Fir | Softwood | $1.75–$3.00 | Structural, decking |
| Poplar | Hardwood | $2.50–$4.50 | Cabinets, furniture, trim |
| Red Oak | Hardwood | $4.50–$7.00 | Flooring, furniture, cabinets |
| White Oak | Hardwood | $5.00–$8.00 | Flooring, whiskey barrels, outdoor |
| Hard Maple | Hardwood | $5.50–$9.00 | Butcher blocks, flooring, furniture |
| Black Cherry | Hardwood | $7.00–$11.00 | Fine furniture, cabinets, veneers |
| Black Walnut | Hardwood | $9.00–$15.00 | Fine furniture, gunstocks, turning |
| Teak | Exotic | $20.00–$35.00 | Outdoor furniture, boat decking |
| Mahogany | Exotic | $12.00–$20.00 | Furniture, boat building |
| Purpleheart | Exotic | $15.00–$25.00 | Decorative, flooring |
Tip: Always add 10–20% extra board feet to account for defects, warp, cut waste, and grain matching. The waste factor field in the calculator above does this automatically.
Log scaling: the Doyle rule
The Doyle log rule is the most widely used method in the eastern United States for estimating how many board feet of lumber can be sawn from a log. It was developed in 1825.
Doyle formula:
BF = ((D − 4) ÷ 4)² × L
Where:
D = small-end diameter inside bark (inches)
L = log length (feet)
Example — 16 in diameter, 16 ft long log:
BF = ((16 − 4) ÷ 4)² × 16
= (12 ÷ 4)² × 16
= 3² × 16
= 9 × 16
= 144 BF
Doyle rule limitations: The Doyle rule significantly underestimates yield for small logs (under 12 inches diameter) and overestimates for very large logs (over 40 inches). For small logs, the International ¼-inch rule or Scribner rule gives more accurate estimates.
FAQs
A board foot (BF) is a unit of lumber volume equal to 1 foot × 1 foot × 1 inch = 144 cubic inches = 1/12 cubic foot. It is used to price and purchase hardwood lumber in the US and Canada. A 1-inch thick, 12-inch wide, 12-inch long board equals exactly 1 board foot.
Board feet = (Thickness in inches × Width in inches × Length in feet) ÷ 12. Example: a board 1.5 in thick × 8 in wide × 10 ft long = (1.5 × 8 × 10) ÷ 12 = 10 BF. To get total cost, multiply by the price per board foot.
Using nominal dimensions: (2 × 4 × 8) ÷ 12 = 5.33 BF. Using actual dimensions (1.5 in × 3.5 in): (1.5 × 3.5 × 8) ÷ 12 = 3.50 BF. Most hardwood suppliers use actual dimensions; construction lumber is often quoted in nominal. Use the toggle in the calculator above to switch.
Nominal size is the rough-cut size before drying and surfacing. Actual size is the finished, smaller dimension. A nominal 2×4 is actually 1.5 in × 3.5 in. A nominal 1×6 is actually ¾ in × 5.5 in. Hardwoods may be sold as 4/4 (1 inch), 8/4 (2 inches), etc. — these refer to rough actual thickness in quarter-inch increments.
When cutting lumber for a project, you lose material to saw kerf (the width of the blade cut), trim cuts at board ends, defects you cut around, and offcuts that are too small to use. A 10–15% waste factor is typical for most woodworking projects. For complex designs with lots of grain matching, use 20%. For simple framing cuts, 10% is usually sufficient.
Softwoods (pine, spruce, fir) cost $1–$3 per BF. Common hardwoods (poplar, oak, maple) cost $3–$9/BF. Premium hardwoods (walnut, cherry) cost $9–$15/BF. Exotic species (teak, purpleheart) cost $15–$35+/BF. Prices vary by region, grade (FAS, Select, #1 Common, #2 Common), and market conditions.