Calculator · Joinery & fasteners
Mortise & Tenon Size Calculator
The free Mortise & Tenon Size Calculator answers one question: Tenon thickness, shoulders and length. Enter your numbers in inches or millimeters and the result updates instantly in your browser, with no sign-up and no app to install. Use it on your phone at the bench, then copy or print the result for your cut list.
Follows the classic one-third rule: the tenon is one third of the stock thickness.
Mortise & Tenon Size
- Tenon thickness
- 1/4″
- Each cheek shoulder
- 1/4″
- Tenon length
- 1 5/32″
- Mortise depth (incl. glue clearance)
- 1 7/32″
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Which other joinery & fasteners calculators help with this project?
- Box Joint (Finger Joint) Calculator — Finger count and exact width for full fingers at both edges.
- Dado & Rabbet Depth Calculator — Safe dado and rabbet depths for your stock.
- Dovetail Angle Calculator — Convert dovetail ratios to degrees.
- Biscuit Size Calculator — Which biscuit (#0, #10, #20) for your stock.
- Pocket holes vs. dowels vs. biscuits — Related guide
What you'll need for this project
Tools
Screws & hardware
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Build it · Intermediate · 1 weekend
Download the complete plan with cut list and materials list (PDF)
Mortise & Tenon Shop Stool — A rock-solid 24″ stool joined with eight mortise and tenon joints. Drawings, cut list with board-foot totals, hardware list and step-by-step instructions.