In a spring-loaded system, the latch springs out from a latch pocket that is built into the door jamb and keeps the door shut. But if you turn the knob or handle, you should be able to retract the latch. That is, unless it’s locked. To unlock this kind of a door, you should be able to take a butter knife or putty knife and manipulate the latch enough to retract it and open the door. The simplest lock to open, though, is the kind with the push button as the locking mechanism. All you will need to do with such a lock is to manipulate the inside of the lock enough to pop the button back out.

A thin knife with a sharp point may be necessary depending on the size of the keyhole, though. You could use a pocket knife if the lock is very small, such as a bike lock. [2] X Research source If the hole in the outside handle is a small circle instead of a slit, you could choose a paperclip or hair clip instead of a knife as it’s safer. If there is a slit on the outside handle, though, a knife should work. [3] X Research source

Stick the blade into the lock as far as it will go. Put it in the bottom half of the keyhole. Apply pressure, first in one direction, and then in the other direction. Basically, you will want to wiggle the knife around in the keyhole. [5] X Research source You may hear a click. If you do, the lock should give a bit. That means you’re in! It can take some time to get the lock open, though.

Pry open the latch by sweeping the end of the knife and moving the latch inward. Take the butter knife, and slide it between the door and the door frame, starting about three inches at the top of the door knob. Slide the knife until you find the door’s bolt. Push the knife in, working it until you slide the bolt out of the door jamb.

Apply twisting pressure to the lock with the knife blade at the same time. If using a paper clip, hammer the end of the paper clip to flatten it before trying to put it in the door. You want to rake the pick across the keyhole pins. You want to be careful not to break the lock or the knife so you may need to carefully wriggle the knife for a while until you hear a click. Insert the tension wrench into the lock opening’s bottom and turn the lock to the side as if you were unlocking the door with a key. Keep holding the tension wrench and apply pressure. Insert the flattened paperclip above the tension wrench, pushing until you meet resistance. Push up on the pin with the paperclip. [7] X Research source

You could also try a credit card if you’re trying to get through a lever-type doorknob. Just slide the card into the crack in the door, where the lock is, similar to the process with a knife. Be aware you might ruin the card, though. [9] X Research source At the same time, put pressure on the door with your free arm so the latch doesn’t spring back out. You may need to make this motion several times before you can get in the door. [10] X Research source