Pocket Hole Screw and Jig Setting Calculator

How it works

A pocket-hole jig drills a stepped hole at a shallow angle through the face of one piece, so a screw can pass out through its end or edge and into the piece it joins. On jigs with a material-thickness scale, the jig's thickness setting matches the thickness of the piece being drilled. How the stop collar on the stepped drill bit is set varies by jig: some have a gauge marked in stock thicknesses, while the Kreg Rocket described by The Family Handyman sets the collar with a 1/8 in gap between the tip of the bit and the built-in stop.

The screw length then follows the drilled thickness. The published chart for the Kreg jig gives 1 in screws for 1/2 in stock, 1-1/4 in screws for 3/4 in stock and 2-1/2 in screws for 1-1/2 in stock such as 2×4s. Those rows are for joining two pieces of the same thickness, so the calculator also reports whether the receiving piece is at least as thick as the drilled one.

Coarse-thread pocket screws are made for softwoods such as pine, and fine-thread screws for hardwoods. Plywood is grouped with softwood.

Formula

jig setting  = drilled piece thickness        (jigs with a thickness scale)
collar gauge = drilled piece thickness        (jigs with a thickness gauge)
screw length = chart[drilled thickness]
               1/2 in → 1 in;  3/4 in → 1-1/4 in;  1-1/2 in → 2-1/2 in
thread       = coarse (softwood, plywood) | fine (hardwood)

Example

Joining 3/4 in pine boards: the jig thickness setting (and the collar gauge setting, on jigs that have one) is 3/4 in, and the chart gives 1-1/4 in coarse-thread screws. The receiving board is also 3/4 in, the case the chart covers.

For 1-1/2 in hardwood the settings are 1-1/2 in and the screws 2-1/2 in, fine thread; for 1/2 in stock they are 1/2 in and 1 in.

Assumptions and limitations

• Screw lengths are the three rows published for the Kreg pocket-hole jig (The Family Handyman, "How to Use Pocket Screws"). Other thicknesses and other makers' jigs have their own charts, which this calculator does not reproduce; the jig maker's instructions are the authority for a given jig.
• The rows are for joining pieces of the same thickness. A thinner receiving piece is flagged as outside the chart rather than given a different screw length.
• Coarse thread for softwood and fine thread for hardwood is the published guidance (The Family Handyman; Wikipedia, Pocket-hole joinery). Grouping plywood with softwood is typical guidance and was not confirmed from a manufacturer source.
• The thickness settings apply to jigs with a material-thickness scale or collar gauge. Jigs that set the collar another way (the Kreg Rocket in The Family Handyman uses a 1/8 in gap between the bit tip and the stop) follow their own instructions.
• This is an estimate, not a substitute for the jig and screw manufacturer's instructions.

Frequently asked questions