How to use this calculator
Enter the width of your tail board (the board that will have the dovetail shapes cut into its end grain) and choose how many tails you want. The calculator divides the width into evenly spaced tails, pins, and half-pins using classic proportions where pins are about one third the width of the tails.
Select the tail angle ratio. Use 1:8 for hardwoods (the most common choice) or 1:6 for softwoods where a steeper angle provides more mechanical grip. The visual diagram shows the actual profile of the joint with the angled tails drawn to scale.
The marking guide at the bottom gives you exact measurements from the edge of the board to each layout line. Transfer these to your workpiece with a marking gauge and knife for a precise layout. The calculator also shows the equivalent angle in degrees if you prefer to set a sliding bevel with a protractor.
Choosing proportions that look right
The beauty of hand-cut dovetails comes from their proportions. Classic English dovetails use narrow pins and wide tails, which creates a strong visual contrast that highlights the joinery. The default settings in this calculator follow that tradition with pins at about one third the tail width and half-pins at half the tail width.
There are no hard rules. Some woodworkers prefer wider pins for a more uniform look. Others make the half-pins very narrow for a refined edge. The best approach is to experiment with different settings in the calculator until you find proportions that look right for your project, then use those measurements at the bench.
Frequently asked questions
How many dovetails should I use?
Two to four tails for drawer-sized work (4 to 8 inches wide). Five to seven tails for wider pieces like blanket chests. Choose what looks proportional to the board width.
What angle should dovetails be?
1:8 (about 7 degrees) for hardwoods, 1:6 (about 9.5 degrees) for softwoods. Steeper angles lock tighter but have more fragile tips. Many woodworkers use 1:8 for all species.
What is the difference between through and half-blind dovetails?
Through dovetails are visible from both sides and used for boxes and carcasses. Half-blind dovetails are hidden from one side, traditionally used for drawer fronts. Half-blind joints are harder to cut since you cannot saw all the way through.
Should I cut tails or pins first?
Most hand-tool woodworkers cut tails first. The tail profile is easier to saw accurately, and you use the cut tails as a template to mark the pins. This "tails first" method produces tighter joints with less fuss.