How to Choose a Deadbolt for Your Front Door

A deadbolt is the main lock on most front doors, and not all of them are equal. Choosing one comes down to a few questions: how it locks, how you want to open it, whether it fits your door, and how well it is anchored into the frame.

What a deadbolt does that a knob lock doesn't

The lock in a doorknob or lever uses a spring latch: an angled bolt that slides shut on its own when the door closes. It is convenient, but it is not built to hold a door against force.

A deadbolt is a solid, square-ended bolt that only moves when you turn the key or the thumb turn. It is much stronger against a forced door, which is why it should be the lock that actually secures the house.

Single cylinder or double cylinder?

• Single cylinder: a key outside and a thumb turn inside. This is the usual choice for a front door.
• Double cylinder: a key on both sides. It is sometimes chosen for doors with glass close to the lock, so that nobody can reach through a broken pane and turn it.

Key, keypad or smart lock?

A keypad deadbolt lets you open the door with a code, so there is no key to lose. A smart deadbolt adds a phone app, and sometimes both. Most keypad and smart models still have a key cylinder as a backup. Our guide to keypad and smart locks goes through the choice in detail.

The part that matters as much as the lock: the strike

When someone tries to force a door, the bolt rarely breaks. What gives is the frame around it. The strike, the metal plate the bolt slides into, is often held by short screws that only reach the thin trim.

• Longer screws that reach the framing behind the trim make the strike much harder to tear out.
• A reinforcement plate spreads the force across more of the frame.
• A deep, clean pocket behind the strike lets the bolt extend fully.

Make sure it fits your door

Most exterior doors are drilled for standard locks, but it is worth checking before you buy:

• Measure the thickness of the door. Very thick or thin doors need a lock made for them.
• Measure the backset: from the edge of the door to the center of the existing hole. Deadbolts come in two common sizes, and many adjust to both.
• Check the existing holes. A new lock that covers the old holes is much neater than one that needs new drilling.

Signs of a good installation

• The bolt slides all the way into the frame without pushing or lifting the door.
• The key and the thumb turn move smoothly, with no scraping.
• The strike sits flush and does not move.
• The deadbolt and the knob lock can use the same key, if you ask for that when you buy them.

If the bolt scrapes or only goes in halfway, the problem is usually where the bolt meets the frame. Our guide on a door that won't lock or latch explains what to check.