A broken door knob is not a particularly difficult to fix. The most common problems result from the broken door knob becoming loose in its fittings or from torque damage to the knob. A broken door knob, however, first has to be assessed as to what type it is. If you have a key-in-knob lock, the repair may be more complicated. If it’s a simple interior knob that’s at issue, the repair is very straightforward. If your broken door knob has a lock in it and is one of the devices you use to secure your home, you may just want to buy a new one rather than risking a bad repair.
First, take the broken door knob and verify that it’s tight in the door. It shouldn’t pull out or wiggle when you pull on it. If it does, the screws that hold the two pieces of the knob together through the door are likely broken or stripped. You can tighten these and this will sometimes fix the broken door knob in one step. If the knob is turning oddly or too stiffly, you should see if loosening or tightening the screws will fix this problem, as well.
Those two screws will also be the first things you need to remove if you have to remove the broken door knob. The door knob can be pulled off by carefully pulling it apart from each side of the door. The latch will be left sitting in the door. If your broken door knob has mechanical damage, it should generally just be replaced. You can often get a replacement for under $20 from most hardware stores. If you want your broken door knob replaced with one that takes the same key as the original, you’ll need to contact a locksmith and ask them to re-key it.