Dado & Groove Calculator

Inputs

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Dadoes cross a panel, grooves usually run with the grain, and stopped cuts need an additional end-stop layout.
Actual shelf, divider, panel or tongue thickness that fits into the slot.
in
Added to mating thickness to set slot width. Positive is looser; negative is tighter.
in
Thickness of the side, shelf, rail or workpiece receiving the dado or groove.
in
Depth of the dado or groove from the reference face.
in
Distance from the reference edge to the near wall of the slot.
in
Router bit diameter, dado stack width or saw kerf used to make the slot.
in
Maximum lateral movement between pass centerlines when the cutter is narrower than the target slot.
in
Length of the dado or groove used for glue-contact area and chip-volume estimates.
in

Results

Default result
Edit inputs
Target slot width(W_slot)
0.755in
Pass

mating part thickness plus fit allowance

Also computed

Cut depth(d_cut)Pass0.25in

shown as a percent of receiving panel thickness

Remaining back thickness(t_back)Pass0.5in

receiving panel thickness minus cut depth

Depth ratio(d/t)Pass33.33%

cut depth / panel thickness

Near wall from edge(x_near)12in

Far wall from edge(x_far)12.755in

Slot centerline from edge(x_ctr)12.377in

Dado and groove layout: 4 pass(es), 0.755 inch slotDado and groove layoutWall marks, cut depth, remaining back thickness and pass layout.target slot widthpasses4depth ratio33.3%remaining back0.500 inNear wall from reference edge12.000 inFar wall from reference edge12.755 inPass spacing0.085 in
Method notes 4 notes
  • Target slot width = mating part thickness + fit allowance.
  • Near wall, far wall and centerline are measured from the same reference edge.
  • Pass count = 1 + ceiling((slot width - cutter width) / max step-over) when the cutter is narrower than the slot.
  • This is a cross-panel dado layout. It does not replace a router-table fence setup, dado-stack shim setup, CNC toolpath, tear-out control, cabinet cut-ticket, structural shelf support check or manufacturer hardware instructions.

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