Pen Blanks From a Board Calculator

The standard pen blank is 3/4" × 3/4" × 5". Slimline kits use 5" blanks. Sierra and Cigar kits use longer (5-1/2" to 6"). Bottle stoppers and seam rippers are usually 1-1/2" or 2" cubes. Set the blank size first.

Rough yield math. A board has three dimensions. Divide each by your blank dimensions and multiply the three together. A 3/4" thick × 6" wide × 36" long board gives:

• 1 × (6 / 0.75) × (36 / 5) = 1 × 8 × 7.2 = 56 blanks (theoretical)

Reality drops that 15 to 25%. Saw kerf eats material. A typical 1/8" table saw kerf removes 1/8" per cut. On a 6" wide board, you get 7 useful 3/4" strips, not 8. On a 36" board, you get 6 to 7 blanks per strip after squaring the ends. So the realistic count for that 3/4" × 6" × 36" board is more like 42 to 47 blanks.

Defects shrink it more. Knots, checks, and pitch pockets are common in cheap blank lumber. If you are buying figured wood (curly maple, burl, spalted), expect 30 to 50% waste on top of kerf — figured wood is sold cheaper for a reason.

Why this matters for kit pricing. A pen kit costs $4 to $30. A premium burl blank costs $5 to $15. Your finished pen is $20 to $80 in materials. If you waste half the board, your effective blank cost doubles, and a $30 pen suddenly sells at break-even.

Tip for figured wood. Cut blanks oversize first (7/8" × 7/8") and trim later after you see how the grain ran. Loses a few blanks per board but means the figure is centered on every pen.

Buying boards versus pre-cut blanks. A 3/4" × 6" × 36" board of cherry might be $25. Pre-cut cherry blanks are $1 to $2 each. The board hits about $0.55 per blank. Boards win on cost. Pre-cuts win on convenience — no saw work, no waste.