Smart Unit ConvertersSmart Unit Converters

Lumber Board Feet Calculator

Calculate board feet for one or many lumber sizes. Add cost-per-board-foot for a total-cost estimate.

Construction

Lumber Board Feet Calculator

Generated on April 25, 2026

Thickness (in)Width (in)Length (ft)QtyBF
53.33
60.00
Total board feet
113.33 BF
Across 2 board types.
$
Lumber stack visualization (relative cross-sections)
10 × 2″ × 4″ × 8ft = 53.33 BF
5 × 2″ × 6″ × 12ft = 60.00 BF

Cross-sections drawn to scale (max width = 6″, max thickness = 2″). Lengths abbreviated.

Step-by-step calculation

Formula

Board feet = (thickness × width × length) ÷ 12, where thickness and width are in NOMINAL inches and length is in feet. Quantity multiplies through.

  1. 11 board foot = a piece 1 inch thick × 12 inches wide × 1 foot long = 144 cubic inches.
  2. 2Use NOMINAL dimensions (a '2×4' is sized as 2 × 4, NOT the actual 1.5 × 3.5).
  3. 310 × (2″ × 4″ × 8ft) ÷ 12 = 5.333 × 10 = 53.33 BF
  4. 45 × (2″ × 6″ × 12ft) ÷ 12 = 12.000 × 5 = 60.00 BF
  5. 5Total: 113.33 board feet.
Why nominal vs actual? A "2×4" piece of dimensional lumber is actually 1½" × 3½" after planing and drying. Lumber yards charge by NOMINAL board feet (the original rough-sawn dimensions), so always calculate with the nominal numbers (2 × 4, not 1.5 × 3.5).

?What is the Lumber Board Feet Calculator?

The Lumber Board Feet Calculator computes the standard 'board foot' (BF) measurement used by every sawmill, lumber yard, and woodworker in the US, Canada, Pakistan, and most of the world. One board foot equals a piece of wood 1 inch thick × 12 inches wide × 1 foot long = 144 cubic inches. The calculator handles multiple board sizes at once (e.g., 10 × 2×4×8' + 5 × 2×6×12' + ...) and totals everything, with optional cost-per-BF input for an instant project budget. Quick-add buttons for the most common dimensional lumber sizes (2×4, 2×6, 4×4, etc.).

The Formula

Board feet = (thickness_in × width_in × length_ft) ÷ 12. Multiply by quantity. Use NOMINAL dimensions (a '2×4' is 2 × 4, NOT the actual planed 1.5 × 3.5).

Board feet is fundamentally a volume measure (144 cubic inches per BF) but uses mixed units — inches for thickness/width, feet for length — because that's how lumber is sold. The /12 in the formula converts the length (in feet) to inches consistently. Always use NOMINAL dimensions when calculating: a 2×4 is sold as 2×4 even though it's actually 1.5×3.5 after planing and drying. Sawmills and lumber yards charge per nominal board foot, not actual.

Practical Examples

1

10 pieces of 2×4 × 8 ft: 2 × 4 × 8 / 12 = 5.33 BF each × 10 = 53.33 BF total.

2

Building a 12×16 ft deck: ~120 BF for the joists (12 × 2×8 × 12 ft) + 200 BF for the decking. Total ~320 BF.

3

Standard pallet of 2×4×8 lumber = ~250 boards = ~1,300 BF.

4

Per-BF prices: SPF (spruce-pine-fir) ~$3-4. Pressure-treated ~$4-5. Cedar ~$6-8. Oak ~$8-12. Walnut ~$15-25.

5

A small kitchen cabinet project: 50-100 BF. A whole-house framing job: 5,000-15,000 BF.

Frequently Asked Questions

Nominal dimensions are pre-planing. After the lumber is rough-sawn (giving the nominal size), it's planed smooth on all four sides ('S4S' = surfaced 4 sides), losing about 0.5 in on each dimension. The lumber industry standardized this around 1900; everyone in the trade knows '2×4 = 1.5 × 3.5'.

Popular Conversions

Jump to a ready-made conversion — useful for quick reference and sharing:

Explore More Tools

Tile Calculator

Calculate the number of tiles needed for any floor or wall, plus waste.

Paint Calculator

Calculate liters of paint needed for walls, accounting for doors and windows.

Concrete Calculator

Calculate cement, sand, and aggregate quantities for your concrete mix.