Board Feet Calculator

Calculate board feet of lumber & logs, estimate costs and build lumber lists with instant conversions.

Lumber Board Feet Calculator

Calculate board feet from lumber dimensions using nominal sizes.

BF = (T × W × L) ÷ 12
Thickness (in) × Width (in) × Length (ft) ÷ 12
LENGTH (FEET) WIDTH THICK 1 BOARD FOOT = 144 in³

Board Feet Results

REMEMBER: Board feet use nominal dimensions (2×6), not actual (1.5×5.5). When buying hardwood, board feet pricing is standard. Softwood (construction lumber) is typically sold by the linear foot or per piece.

Log Board Feet Calculator

Estimate board feet yield from logs using Doyle, Scribner, or International ¼" scale.

Log Board Feet Results

LOG SCALES: Doyle underestimates small logs, overestimates large. Scribner is used by the USFS for softwood. International ¼" is the most accurate for actual lumber yield. Typical sawmill yield: 50-65% of log volume.

Lumber Cut List — Multi-Item BF Calculator

Build a complete lumber list and calculate total board feet.

Lumber List Total

Lumber Cost Estimator

Calculate lumber costs by board foot price or per-piece pricing.

Lumber Cost Estimate

SAVE MONEY: Buy rough-sawn lumber from local sawmills (30-50% cheaper). S4S (surfaced 4 sides) costs $1-3/BF more. Buy in bulk for volume discounts. Check for #2 grade — often 20-30% cheaper with minor cosmetic defects.

Board Feet Reference Tables

Common Lumber — Board Feet per Piece

Size 8' 10' 12' 16' 20'
1×4 2.67 3.33 4.00 5.33 6.67
1×6 4.00 5.00 6.00 8.00 10.00
1×8 5.33 6.67 8.00 10.67 13.33
1×12 8.00 10.00 12.00 16.00 20.00
2×4 5.33 6.67 8.00 10.67 13.33
2×6 8.00 10.00 12.00 16.00 20.00
2×8 10.67 13.33 16.00 21.33 26.67
2×10 13.33 16.67 20.00 26.67 33.33
2×12 16.00 20.00 24.00 32.00 40.00
4×4 10.67 13.33 16.00 21.33 26.67
6×6 24.00 30.00 36.00 48.00 60.00

Board Feet to Other Units

Conversion Value
1 Board Foot 144 cubic inches
1 Board Foot 1/12 cubic foot
1 Board Foot 2,360 cm³
12 Board Feet 1 cubic foot
1,000 Board Feet (MBF) 83.33 cubic feet
1 Board Foot (sq ft coverage) 1 sq ft at 1" thick

Hardwood Lumber Grades

Grade Clear Face Min Size Use
FAS (First & Seconds) 83%+ 6"×8' Fine furniture, cabinetry
FAS 1-Face (F1F) 83%+ one side 6"×8' Furniture, visible one side
Select 83%+ one side 4"×6' General woodworking
#1 Common 67%+ 3"×4' Kitchen cabinets, flooring
#2 Common 50%+ 3"×4' Crates, pallets, rustic

How to Calculate Board Feet

The board feet formula is simple: BF = (Thickness × Width × Length) ÷ 12, where thickness and width are in inches, and length is in feet. One board foot equals 144 cubic inches — a piece 1" thick × 12" wide × 1 foot long.

Board Feet Examples

  • 2×4×8' = (2 × 4 × 8) ÷ 12 = 5.33 BF
  • 2×6×12' = (2 × 6 × 12) ÷ 12 = 12 BF
  • 1×8×10' = (1 × 8 × 10) ÷ 12 = 6.67 BF
  • 4/4 (1") × 6" × 8' = (1 × 6 × 8) ÷ 12 = 4 BF

Calculating Board Feet of a Log

The Doyle Log Scale is the most common: BF = (D − 4)² × L ÷ 16. A 16" diameter, 12' log yields (16−4)² × 12 ÷ 16 = 108 board feet. The International ¼" rule is more accurate for small logs.

Frequently Asked Questions

How many board feet in a 2×4?+
Per foot of length: (2×4)/12 = 0.667 BF per linear foot. Common lengths: 8' = 5.33 BF, 10' = 6.67 BF, 12' = 8 BF, 16' = 10.67 BF. Board feet use nominal (not actual) dimensions.
Board feet to square feet?+
Board feet ÷ thickness (inches) = square feet. 100 BF of 1" lumber = 100 sq ft of coverage. 100 BF of 2" lumber = 50 sq ft. For 4/4 (1" thick) hardwood, board feet equals square feet.
What does 4/4, 5/4, 8/4 mean?+
These are quarter fractions of thickness in inches: 4/4 = 1", 5/4 = 1¼", 6/4 = 1½", 8/4 = 2", 12/4 = 3", 16/4 = 4". This is the standard way hardwood lumber thickness is specified. Rough-sawn boards are cut to these thicknesses before drying and planing.