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Board Feet Calculator

Supports multiple lumber piecesOptional cost estimatorNominal vs actual size reference
Enter Lumber PiecesFree · Instant
Thick (in)
Width (in)
Length (in)
Qty
BF
0.33
Results
0.33
Total Board Feet

The Board Feet Formula

BF = (Thickness × Width × Length_inches) ÷ 144
Or: (Thickness × Width × Length_feet) ÷ 12

A board foot measures lumber volume. One board foot equals a 1-inch thick, 12-inch wide, 12-inch long piece of wood, or any equivalent volume.

Example: A 1" × 6" × 8 ft board = (1 × 6 × 8) / 12 = 4 board feet.

Who Is This Calculator For?

🪵
Woodworkers
Plan material purchases for furniture, cabinets, or custom builds.
🏗️
Contractors
Estimate lumber costs before bidding on framing or finishing work.
🏠
DIY Builders
Calculate how much wood you need before visiting the lumber yard.
💰
Budget Planners
Get cost estimates by entering price per board foot.

How to Use This Calculator

1
Enter thickness in inches
Use actual dimensions, not nominal. A 2×4 is actually 1.5 inches thick.
2
Enter width in inches
Again, use actual width. A 1×6 board is actually 5.5 inches wide.
3
Enter length in inches
Length can be entered in inches (e.g., 96 for an 8-foot board).
4
Enter quantity
How many pieces of this size do you need?
5
Add more rows
Click 'Add Row' to add additional lumber sizes to your project.
6
Enter price per board foot
Optional: if you know the cost per BF, get an instant cost estimate.

Worked Example

James is building a workbench and needs ten 2×4×8 ft boards and five 1×12×6 ft boards.

Ten 2×4×8: (1.5 × 3.5 × 96) / 144 × 10 = 35.0 BF
Five 1×12×6: (1 × 12 × 72) / 144 × 5 = 30.0 BF
Total: 65.0 board feet
At $3/BF: $195.00 estimated cost

Common Mistakes to Avoid

!
Using nominal instead of actual dimensions
A 2×4 is 1.5" × 3.5", not 2" × 4". Using nominal sizes overstates your board feet by about 30%.
!
Forgetting to add a waste factor
Always add 10–15% for cuts and defects. Enter slightly more than your exact need.
!
Confusing board feet with linear feet
Linear feet measures length only. Board feet accounts for thickness and width too.
!
Not accounting for species pricing differences
Hardwoods and softwoods are priced per BF, but rates vary dramatically by species.
!
Mixing inches and feet in the same entry
Enter all dimensions in consistent units. This calculator uses inches for all dimensions.

Frequently Asked Questions

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Sources & References

National Hardwood Lumber Association: Grading Rules & Board Foot Standards
NHLA · nhla.com
Wood Handbook: Wood as an Engineering Material
USDA Forest Service · fpl.fs.usda.gov
Voluntary Product Standard PS 20-15
American Lumber Standard Committee · alsc.org
Written By
Jake Morgan
Woodworker & construction estimator, 18 years experience

Jake has worked in residential construction and custom woodworking for nearly two decades. He specializes in material estimation and teaches woodworking at a community college in Oregon.

Nominal vs Actual Size
NominalActual
1×43/4" × 3½"
1×63/4" × 5½"
1×83/4" × 7¼"
1×103/4" × 9¼"
1×123/4" × 11¼"
2×41½" × 3½"
2×61½" × 5½"
2×81½" × 7¼"
2×101½" × 9¼"
2×121½" × 11¼"
💡 Pro Tip

Lumber yards price by nominal dimensions. When comparing prices, check if the price is per board foot based on nominal or actual size, it matters for thick hardwood slabs where the difference can be 20–30%.

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