Comparing Deadbolts, Knobs, Levers, and Handlesets
| Lock type | How it holds the door | Best used on | Keep in mind |
| Single-cylinder deadbolt | Solid bolt; key outside, thumbturn inside | Every exterior door | The standard choice for most homes |
| Double-cylinder deadbolt | Solid bolt; key on both sides | Doors with glass near the lock | Needs a key to get out, which slows escape in a fire |
| Knob lockset | Spring latch | Interior doors, or with a deadbolt outside | The latch alone is easy to slip or force |
| Lever lockset | Spring latch | Any door, especially for kids and older adults | Opens with an elbow or full hands |
| Handleset | Thumb-latch grip outside, knob or lever inside | Front doors | Usually paired with a matching deadbolt |
| Keypad deadbolt | Bolt opened by code or key | Rentals, busy households | Batteries; see smart lock installation |
Reading the BHMA label
BHMA rates residential locksets (A156.39) and deadbolts (A156.40) with three separate letters for security, durability, and finish, where C is good, B is better, and A is best. To earn an A for durability under A156.40, a deadbolt has to survive 400,000 cycles, and its security tests include holding against 1,350 pounds of force loaded on the bolt.
Commercial hardware uses a Grade 1, 2, 3 scale instead. A Grade 1 bored lock under A156.2 is tested to 1,000,000 cycles, and a Grade 1 deadbolt under A156.36 to 250,000 cycles with the same 1,350 pound load. For pick and copy resistance too, see high-security locks.
Sources: BHMA Hardware Highlights (A156.40-2025, A156.2-2022, A156.36-2020) and the BHMA homeowner FAQ.