What Is a Board Foot?
A board foot (BF) is a volume measurement equal to 1 ft x 1 ft x 1 inch (144 cubic inches). It is the standard unit for buying and selling rough-cut lumber in North America.
Formula: Board Feet = (Thickness in inches x Width in inches x Length in feet) / 12. A board 1 inch thick, 12 inches wide, 8 feet long = 8 board feet.
For logs, the yield depends on diameter, length, and scaling method. Three major scales exist because no single formula perfectly predicts lumber recovery from a round log.
Use our Log Volume Calculator to compute board feet using Doyle, Scribner, or International scales.
The Three Major Log Scales
Doyle Scale (1825): BF = ((D - 4) squared x L) / 16. Most common in Eastern US. Underestimates small logs (10-30% for logs under 16 inch diameter).
Scribner Scale (1840s): Geometric method drawing 1-inch boards inside the cross-section. More accurate for 8-20 inch logs than Doyle.
International Scale (1920s): Most mathematically accurate. Uses the Smalian formula. Within 3-8% of actual yield across all sizes. Preferred by government agencies.
The same 16 inch x 16-foot log yields: 49 BF (Doyle), 52 BF (Scribner), 59 BF (International) — a 20% spread that means real money at $3-8/BF.
- Doyle underestimates small logs by 10-30%
- Scribner is most accurate for 8-20 inch logs
- International is the gold standard
- Same log yields 20% different results across scales
Wood Species and Pricing
Softwoods: White Pine ($3-5/BF), Douglas Fir ($4-7/BF), Southern Yellow Pine ($3-6/BF), Western Red Cedar ($8-15/BF).
Hardwoods: Red Oak ($6-10/BF), White Oak ($8-12/BF), Black Walnut ($12-25/BF), Cherry ($8-15/BF), Maple ($5-9/BF).
Weight matters: Oak ~47 lbs/cubic ft (green), Pine ~31 lbs, Walnut ~38 lbs. A full cord of green oak weighs ~5,000 lbs.
Yield rates: Softwood logs yield 50-65% usable lumber. Hardwood logs yield 40-55%. The rest becomes sawdust, slabs, and edgings.
Accuracy Comparison
Doyle: Underestimates by 10-30% for logs under 16 inch. A 12 inch x 16-foot log: Doyle predicts 36 BF but actual yield is ~48 BF (25% underestimate).
Scribner: Within 5-10% for 10-20 inch logs. Good balance of simplicity and accuracy.
International: Within 3-8% across all sizes. The gold standard for government timber sales.
At $5/BF, a 10% error on a 200 BF log = $100. Over a 5,000 BF truckload, that is $500.
Sawmill Tips
Know which scale your buyer uses before negotiating. Doyle shortchanges sellers on small-medium logs.
Sort logs by species and size before scaling. Mixing species reduces bargaining power.
Factor in 8-15% saw kerf waste. Bandsaws (0.05-0.1 inch kerf) recover 10-20% more than circular saws.
Custom sawing high-value species (Walnut, Cherry) into specific dimensions can double or triple value vs raw logs.
Frequently Asked Questions
Which log scale should I use?
International Scale is most accurate. Doyle is traditional in Eastern US. Know your local market expectations.
How do I measure log diameter?
Measure at the small end, subtract bark (0.5-1 inch), round down to nearest inch. Measure perpendicular to growth rings.
Board feet vs cubic feet?
1 BF = 144 cubic inches = 0.0833 cubic feet. 1 cubic foot = 12 BF. Conversion depends on sawing efficiency.
How much lumber from 1000 BF log?
After kerf waste (8-15%) and defects, expect 850-920 BF of usable lumber.
Pricing per board foot or per log?
Most timber is priced per BF. Softwoods $3-7, common hardwoods $6-12, premium hardwoods $12-25/BF.