Dovetail Spacing Calculator

Inputs

View results
Width across the dovetail layout.
in
Thickness used to estimate the angled side offset.
in
Optional slope guide. Common shop convention uses steeper 1:6 slopes for softwoods and shallower 1:8 slopes for many hardwoods.
Number of full tails across the board. Edge pins are treated as half pins.
tails
Full pin width divided by full tail width.
Slope is expressed as rise:run across the dovetail side. 1:6 is steeper than 1:8.

Results

Default result
Edit inputs
Full tail width(T_w)
0.6897in
Pass

4 full tails.

Also computed

Full pin width(P_w)Pass0.3103in

Full pin width; edge pins are half this.

Edge half-pin width(P_e)0.1552in

Tail layout pitch(p)1in

One full tail plus one full pin width.

Side offset through thickness(o)0.125in

From 1:6 slope through the board thickness.

Tail side angle(a)9.462°

Slope 1:6.

Slope denominator(x)6for 1:x

Equivalent slope 1:6.

Dovetail layout across board width board width divided into 4 equal pitches T1 T2 T3 T4 Edge pins are half of the full pin width; internal pins use the full pin width. Guidance: recommended slope 1:6; max cleanup chisel 0.264 in.
Method notes 5 notes
  • Layout assumes equal-width tails, equal full pins, and two edge half-pins that together equal one full pin.
  • Formula: tail width = board width / (tail count x (1 + pin-to-tail ratio)); pin width = ratio x tail width.
  • Species slope guide: Eastern white pine maps to 1:6. Use it as a starting convention, not a rule.
  • Max cleanup chisel width is a practical screen for clearing the narrowest full pin/tail gap; pick the next smaller chisel in your rack.
  • This is a marking and spacing aid only. It does not account for saw kerf, paring allowance, wood movement, grain, glue clearance, joint strength or left/right board orientation.

Powered by MachineCalcs ↗