One of the worst things that can happen at a party or large family gathering is not having access to the bathroom because the door was accidentally locked from the inside. There are two major types of doorknob locks; push button and turning tab. Push button locks have a button on the inside of the door that, when pushed, locks the door. A hole is on the outside knob. The turning tab lock has a tab on the inside that locks when it is turned to the left or right. The outside knob has a slot. Fortunately both of these bathroom door locks are easy to open.
Push button Locks
Unfold a paper clip so that the end is straight.
Stick the straight end of the paper clip into the hole on the outside of the doorknob.
Push the paper clip until a popping sound is heard. A button inside the knob will push on a rod or lance that pops the lock open.
Turning Tab Locks
Insert the head of the regular flathead screwdriver into the slot on the outer knob. If the turning tab lock has a keyhole on the outside knob, skip to step 3.
Turn the screwdriver counterclockwise to turn the tab and open the lock.
Stick the tiny flathead screwdriver into the keyhole on the outside knob. There is a slot inside the knob that the screwdriver must fit into. Give the screwdriver a quarter-turn clockwise, which will unlock the door. This may take a few attempts.