Dovetail Calculator

Inputs

Dovetail type

Male: measure over the pins off the wide base flat. Female / socket: measure between the pins off the narrow throat opening.

Dovetail angle (α)

Included angle from the base; 60° is most common.

Pin / rod diameter (D)

Diameter of the two cylindrical pins or rods seated in the acute corners.

Flat width (W)

Base (wide) flat for a male dovetail; throat (narrow top opening) for a female dovetail.

Default result

Measurement(M)

67.3205mm

Pass

over pins

Also computed

Pin constant(k)2.7321

k = 1 + cot(α/2); 2.732 at 60°.

Method notes 4 notes

Pin constant k = 1 + cot(α/2) = 2.73205 for α = 60°.
Male dovetail: M = W + D·k — measure over the two pins, with W the wide base flat.
At α = 60°, k = 1 + cot30° = 2.7320508 — the classic "add 2.732 × pin diameter" rule.
The pin diameter must be chosen so each pin seats fully on the sloped face, contacting both surfaces and not bottoming in the corner.