Lumber Yield Calculator — Usable Wood from Rough Stock

Lumber yield is the percentage of usable, defect-free wood you get from rough stock. Starting with 100 board feet of rough lumber, you might end up with 50–70 board feet of usable material after removing defects, planing, and cutting.

FAS (First and Seconds) is the highest grade with fewest defects, yielding about 83% clear wood. Select is next at about 75%. No. 1 Common yields about 67%, and No. 2 Common about 50%. Lower grades cost less but produce more waste.

Planing typically reduces board footage by 10–15%. A 25mm (1-inch) rough board planed to 20mm loses 20% of its thickness. Width losses from edge jointing add another 5–10%. The calculator default of 15% covers both.

Divide the board feet you need by the expected yield. If you need 50 BF of usable oak and expect 65% yield, buy 50 ÷ 0.65 = 77 BF of rough stock. Always round up and add a small buffer.