How to Install a Deadbolt Lock on a Door | Secure It In 8 Steps

One wrong measurement or a crooked drill hole, and that new deadbolt either binds or misses its strike plate entirely, leaving your door less secure than when you started. The fix is straightforward if you move through the process in the right order, paying attention to alignment at each stage. Whether you are replacing an old lock or adding a deadbolt to a door that never had one, these steps work for a standard wood exterior door with a separate jamb.

Mark the Height and Centerline

Measure up from the bottom of the door and mark that height on the door face. Then find the center of the door edge and mark that same height there — this gives you the two reference points you will drill into. Adjust the height if you have a storm door or existing hardware that would interfere.

Drill the Main Hole and the Edge Hole

Transfer the lock manufacturer’s paper template to the door face, centering it on your height mark. Tape it in place and mark the center of the main hole. Using a hole saw, drill a 2-1/8-inch hole through the door face. Go about halfway from the outside, then finish from the inside — this prevents splintering the wood on the far side. Then drill a 1-inch hole into the door edge at your marked centerline point, so it meets the main hole cleanly.

Mortise the Latch Faceplate and Fasten It

Insert the latch assembly into the edge hole and trace around its faceplate with a utility knife. Remove the latch and chisel out a shallow mortise so the faceplate sits flush with the door edge. This is usually about 1/8 to 1/4 inch deep, depending on the hardware. Set the latch into the mortise and fasten it with the two small screws that came with the lock.

Install the Deadbolt Body and Test the Turn

Slide the exterior half of the deadbolt through the main hole from the outside, aligning its tailpiece with the latch mechanism. From the inside, attach the interior half and secure it with the provided machine screws. Tighten them enough to hold the assembly snug but not so tight that the lock binds — turn the thumbturn to confirm the bolt moves smoothly in and out.

Mark and Mortise the Strike Plate

Close the door and mark where the deadbolt latch touches the door jamb. Drill a recess hole about 1 inch deep into the jamb at that spot so the bolt has room to extend fully. Trace the strike plate over the recess, chisel a flush mortise into the jamb, and fasten the strike plate with screws. Upgrade those screws to 3-inch security screws for much better bite into the door frame — standard short screws pull out too easily on a kick-in attempt.

Common Mistakes to Avoid

• Misaligned template or centerline: the bolt and strike plate will miss each other, and you will be drilling fresh holes into a door that now has two sets of them.
• Drilling at an angle: keep the drill perpendicular to the door face; an angled hole causes the lock to bind and wear unevenly.
• Mortise too deep or too shallow: a latch faceplate that sits above the surface catches clothing and looks unfinished; one that sinks too far leaves a gap that collects dirt.
• Forgetting the jamb recess: without it, the deadbolt cannot fully extend, and the door will not lock securely.
• Over-tightening screws: bind the mechanism and make the key or thumbturn stiff to operate.

If you are shopping for a new lock and want to compare options side-by-side, our tested guide to the best exterior door lock sets with deadbolts covers models that fit standard backsets and door thicknesses without extra hassle.

Door Compatibility Notes

These instructions assume a standard wood exterior door with a separate door jamb. If your door is steel, fiberglass, or an unusually thick custom model, the drilling and mortising steps may differ — always check the manufacturer’s installation guide first. For storm doors, measure carefully to avoid hardware interference from the existing closer or handle. And if the lock manufacturer specifies a different hole size or backset dimension than the common 2-1/8-inch and 1-inch defaults, follow the lock’s template exactly rather than the general numbers here.