Dovetail Calculator
Even tail spacing and marking angle for any board width
Marking Angle
8.1°
Tail Width (at baseline)
0.75in
Pin Width (at baseline)
0.30in
Half-Pin Width (each edge)
0.15in
How to use this dovetail calculator
Enter your board width and how many tails you want, pick an angle ratio (1:8 is the traditional hardwood standard, 1:6 for softer woods since a steeper angle would risk short grain breaking out). This divides the width into evenly spaced tails and pins, with half-pins at each edge, and gives the marking angle for your dovetail gauge or bevel.
How the spacing is calculated
Angle = arctan(1 ÷ ratio)
Pins are set at 40% of tail width — narrower pins are traditional for both strength (more glue surface on the tails) and look
Pins are set at 40% of tail width — narrower pins are traditional for both strength (more glue surface on the tails) and look
This gives evenly spaced dovetails as a reliable starting layout — many hand-cut dovetail joints use deliberately uneven spacing for a more organic look, which is a style choice this tool doesn’t try to replace. Use these numbers as your baseline, then adjust by eye if you want that traditional hand-cut variation.