Deadbolt Types: What Goes Where

Key outside, thumb-turn inside. The most common residential deadbolt. Fast exit in an emergency. Standard choice for solid exterior doors without glass near the lock.

Key both sides. More secure if there's glass near the lock (no reaching in to unlock), but slower to exit in a fire. Some jurisdictions and insurers restrict them. Confirm compatibility before installing.

Common on older apartment doors. A vertical bolt engages a surface-mounted strike, resisting prying. Installation quality varies — many older units are Grade 3 and worth upgrading.

Electronic keypads, phone unlock, temporary codes. Convenience comes at the cost of batteries and firmware. See smart lock vs traditional.

A Grade 1 deadbolt with a short strike plate secured by half-inch screws into the door jamb offers less protection than a well-installed Grade 2 with three-inch screws into the wall framing. Reinforced strike plates make more difference than most homeowners realize.