Ask a Prepper Explains How to Estimate Board Feet in a Log

Ask a Prepper has published a guide for homesteaders who mill their own logs, showing how to estimate a log's usable lumber before spending work, fuel and blades on it.

Key points

• Two measurements: Take the small-end diameter inside the bark, averaging two readings at right angles if the end is oval, plus the length in feet. Every board has to fit inside that small end.
• Board foot: A board foot is a piece 12 inches square and 1 inch thick, so an 8-foot 2x4 holds about 5 1/3 board feet.
• Three rules: Doyle, the oldest and simplest formula, badly undercounts small logs. Scribner, common in the West, usually lands in between, and International 1/4-inch accounts for saw kerf and taper.
• Sample figures: For 16-foot logs, the guide lists a 12-inch log at 64 board feet under Doyle versus about 95 under International, 16 inches at 144 versus about 180, and 20 inches at 256 versus about 290.
• Milling tips: Start with straight, sound logs, leave a few extra inches for trimming, stack and sticker boards right away, and allow roughly one year of air-drying for each inch of thickness.

Quick take

The guide's view is that International 1/4-inch comes closest to what a home sawyer will get, and that the gap between it and Doyle on small logs, known as overrun, works in the miller's favor. It notes Doyle is still widely used in eastern and southern log buying.

Read the full story at Ask a Prepper.