If your home has a door that can be easily locked, chances are you have accidentally locked this door shut by accident. This fairly routine problem can turn serious when somebody really needs to use that bathroom, or when a small child gets locked in a room by mistake. For these reasons, homeowners should familiarise themselves with the locking mechanisms of all the doors in their home, and make sure that they can access any locked door fairly quickly if the need arises.
Straighten a paper clip so that it is 3 inches long, and push it straight into the doorknob hole until you feel it meet resistance. Continue to press until you feel the resistance yield slightly. Have your hand on the doorknob so that you can open the door as soon as the lock is released. This technique may require some practice and works only on doorknobs with small holes.
Insert a credit card into the crack between the door and the doorjamb, where the locking mechanism is located. Slide the edge of the credit card up to the visible section of the lock and try to work the locking pin over toward the door. This will require some practice, and it may be helpful to practice with the door open, or with someone on the other side of the door to open it for you. Once mastered, this is a useful skill.
Remove the entire doorknob assembly, using a screwdriver if necessary. When all other lock-opening methods have failed, the last resort is to remove the doorknob. Some doorknobs do not have screws on the outside of the door, but many do, particularly indoor knobs for bathrooms where security is not a priority. Unscrew all the screws and wiggle the doorknob until the entire mechanism detaches. You may need to unscrew some parts of the doorknob within the mechanism as well.
Keep keys for each lockable door in your home within easy access of the door itself. Nearby drawers, desks and hidden nails behind furniture are great places to keep keys for often-used and locked rooms such as bathrooms. Keep a well-labelled set of all the master keys in a secure location that you can easily access in an emergency. Lockpicking kits are an excellent way to unlock a tricky door, but they require some experience and instruction. Have someone teach you to use a lockpicking kit, or study the instructional videos available online.
Home doors that cannot be accessed and unlocked from the outside of the room are dangerous and the doorknobs and locking mechanisms of these doors should be replaced. Extreme methods of opening locks may cause damage to the lock or the door, so avoid using metal shears, hammers or breaking down doors except as a last resort.