Use this workshop calculation to turn measured dimensions and the selected construction convention into a cut, spacing, fit, or material-planning value.

Joint width (mm)

Width of the jointed workpiece in millimeters.

Desired pitch (mm)

Desired distance between pin centers in millimeters.

Compute an even finger joint pitch that fits a whole pin count into the joint width. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Pin count

Whole number of pins that fit the joint width.

Adjusted pitch (mm)

Evenly distributed pitch in millimeters.

• Nominal dimensions, kerf, moisture movement, hardware clearances, wall squareness, and manufacturer instructions can change the required shop dimension. Measure the actual assembly and test critical joints on scrap before cutting finished material.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Complement the calculated dimension with a physical story stick, dry fit, or full-size layout. Follow the hardware, coating, adhesive, or machine manufacturer's limits where they differ from a rule of thumb.

• Dovetail Tail Count

  Count complete dovetail tails that fit an available joint width after reserving equal end pins and interior pin widths.

• Box Joint Finger Width

  Divide board edge width into a specified number of equal-width box-joint fingers.

• Dovetail Pin Width

  Solve equal interior pin width from joint width, two end pins, tail count, and equal tail width.