Dovetail Spacing Calculator

How it works

Pins = tails + 1 · Tail width = (board width − pins × pin width) ÷ tails · Tail pitch = board width ÷ tails

Handsome dovetails come from a deliberate rhythm of pins and tails rather than guesswork. Fix the narrow pin width first — that is set by your saw kerf and how fine you want the look — then divide the leftover width evenly among the tails. A joint with N tails always has N+1 pins because there is a pin between every pair of tails plus a half-pin at each edge, which is what keeps the corners from crumbling. Starting and ending with a half-pin (rather than a half-tail) is the traditional choice: it puts solid material at the vulnerable edges and reads as balanced. Widen the pins for a rugged, hand-cut look or narrow them toward the classic London pattern.

Worked example

A 6″ drawer side with 4 tails and 1/4″ pins: pins = 4 + 1 = 5, taking 5 × 1/4 = 1-1/4″. The remaining 4-3/4″ splits into four tails of about 1-3/16″ each at the baseline, with a 1/8″ half-pin at each edge. Tail pitch is 6 ÷ 4 = 1-1/2″ centre to centre.

Frequently asked questions