When a door latches properly, the spring bolt rides up the angled face of the strike plate and drops into the hole with a click. It only takes a misalignment of about an eighth of an inch, in any direction, to break that. The door still swings shut — it just won't stay shut, or it catches only when you lean on it. The cure is almost never a new door or a new lock. It's finding which direction the bolt is missing in, and correcting that one direction.
Don't guess. Each direction of miss has a different fix, and the test takes about a minute.
Mark the bolt. Smear a little lipstick or chalk on the end of the latch bolt, or stick a small piece of painter's tape across it. Close the door gently, without forcing it, then open it and read the strike plate. The mark transfers to wherever the bolt actually lands — above the hole, below it, or off to one side. That transfer mark is your diagnosis.
Do the lift test. Grip the knob and lift the door slightly as you close it. If it latches cleanly while lifted, the door is sagging on its hinges. That's the most common result, and it's a hinge fix, not a plate fix.
Check the gap. With the door closed, look at the reveal — the gap between door and frame. It should be roughly even all the way around. A gap that's wide at the top on the latch side and pinched at the bottom confirms the sag. If the gaps look even but the bolt still misses sideways, the frame has likely shifted or the house has settled a little.
Sagging is a hinge problem, so start there. Moving the strike plate to match a sagging door works for a while, but the door keeps moving and you'll be moving the plate again next year.
Tighten every hinge screw. Start with the top hinge — it carries the most load and works loose first. If a screw spins without biting, its hole is stripped: pack the hole with two or three glue-coated toothpicks, let the glue set, then drive the screw back in. While the screws are out, if the hinges have developed a squeak, our guide to why door hinges squeak covers the quick cure.
Add one long screw to the top hinge. Take out a screw on the jamb side of the top hinge and replace it with a 3-inch screw. The longer screw passes through the jamb and bites into the wall stud behind it, pulling the whole hinge side in. That lifts the latch side of the door — exactly the move you want when your mark showed the bolt hitting low.
Shim the hinge that's causing the miss. Bolt hitting high instead? Slip a cardboard shim behind the top hinge leaf, between the leaf and the jamb — that tips the latch side down a touch. Bolt hitting low with all screws tight? Shim the bottom hinge instead, which tips the latch side up. One cereal-box thickness moves the bolt roughly 1/16 inch at the plate, so add or remove layers until it clicks.
File the hole a little bigger. If the miss is small — an eighth of an inch or less — you don't need to move the plate at all. A few strokes of a metal file on the edge of the hole where the bolt is hitting opens it up enough. Cheap, invisible, done in two minutes.
Or move the plate. For a bigger miss, take the plate off, fill the old screw holes with glued toothpicks, and remount the plate shifted the way the bolt needs to go. You may have to shave a sliver of wood from the mortise with a chisel so the plate sits flush. There's also a shortcut hardware stores sell: an adjustable strike plate, with slotted holes and a bendable tab, that forgives small errors without new holes.
Mind the small plunger. On most keyed knobsets, the bolt has a smaller secondary plunger beside it. That plunger is supposed to rest on the flat surface of the strike plate — it's what locks the bolt against being slipped open with a card. If the bolt and the plunger both drop into the hole, the door feels loose and that protection is defeated. The opening in the plate should catch the big bolt only.
Sometimes the bolt, hinges, and plate are all innocent. Sight down the edge of the door from the hinge side: if the edge bows, the door is warped, and no plate position will latch it in every season. Humidity does a milder version of the same thing — a door that latches fine in February swells in August and starts missing by a hair. If yours is seasonal, resist planing or big adjustments at the peak of summer; you'll overcorrect and own a sloppy, rattling fit all winter. A door swollen enough to rub and bind against the frame is a different repair from a latch miss, and our guide to fixing a door that sticks covers that side of it.
A worn latch mechanism is the last suspect. If the bolt doesn't spring out to its full length, or the knob feels gritty and loose in your hand, the latch itself is dying. Knobsets are cheap and swap in a few minutes with the door still hanging; no alignment trick compensates for a bolt that only pokes out halfway.
Moving the strike plate first. It's the most visible fix and the least permanent when the real problem is sag. You'll also leave a trail of filled holes in the jamb for the next person to puzzle over.
Slamming it until it catches. A door that needs a shoulder to latch is telling you something. Slamming bends the bolt, works the hinges looser, and can crack the trim around the frame.
Filing the hole wide open. An oversized hole latches, yes — and then the door rattles in every draft. File a little, test, file a little more.
Planing the door in August. Wood swells with humidity. Every shaving you take off in summer is a gap you'll be looking at all winter.
Mark the bolt, read where it lands, and fix that one direction: tighten or shim the hinges for a sag, file or shift the plate for a small miss. Most doors that won't latch are a single hinge screw away from clicking shut the way they used to.
Humidity. Wood doors and frames absorb moisture in summer and swell, but they don't swell evenly, so a bolt that lined up in dry winter air can miss by a hair in August. If the door latches again when the heat comes on, the fix is patience or a very small strike plate adjustment — not planing.
Use the lipstick test. Coat the end of the latch bolt with lipstick, chalk, or a bit of painter's tape, close the door once, gently, and open it. The mark left on the strike plate shows exactly where the bolt lands relative to the hole.
Yes. Every standard fix on this page — tightening screws, the long screw in the top hinge, shims, filing or moving the strike plate — is done with the door hanging in place. Removing the door is only necessary for planing an edge or replacing a badly warped door.
The bolt is seating, but there's play between the door and the frame. Most strike plates have a small bent tab inside the hole; bending that tab slightly toward the door takes up the slack. A felt or rubber pad on the door stop works too, and takes ten seconds.
When several doors in the house go out of alignment around the same time, especially with new cracks in the wall above the frames or gaps that keep growing. One tired door is hardware. A pattern of doors is the frame — and possibly the structure under it — moving, and that's worth having a professional look at. Floors tell the same story from underneath: our guide to sloping floors in an old house covers which slopes are old-house normal and which ones aren't.