Single Cylinder vs. Double Cylinder Deadbolt

Single Cylinder vs. Double Cylinder Deadbolt: Which One to Buy?

Having an elegant front door to your home is an effective way to create a lasting impression on your visitors. However, having a sleek door is not enough to secure your home. You need a properly functioning deadbolt to deter intruders from breaking into your home.

Deadbolts can be different, either single-cylinder or double-cylinder. The type of deadbolt can make a difference in how secure and convenient your home is.

Single-cylinder deadbolts require a key to lock and unlock from the outside. On the other hand, double-cylinder deadbolts require a key on both sides of the door. Single cylinder deadbolts have a thumb-turn for locking and unlocking it from inside. Double-cylinder deadbolts do not have this feature.

This article advances the single-cylinder vs. double-cylinder deadbolt debate, providing the meaning of each, pros, and cons. Keep reading to learn more about these deadbolts.

What Is a Single Cylinder Deadbolt?

Single cylinder deadbolts are those operated with a key only on the outside. On the inside, a single cylinder lock doesn’t require a key to lock and unlock. A simple thumb-turn mechanism is enough to lock and unlock the deadbolt from the inside.

While this type of lock is mainly available in traditional form, you can also get it as a single-cylinder smart lock. Once set correctly, a smart lock doesn’t require rekeying to lock or open. All that’s important is a Kwikset key.

Pros And Cons of  Single Cylinder Deadbolts

What are the advantages and disadvantages of having a single-cylinder vs. a double-cylinder deadbolt? Single-cylinder locks have several pros and cons, including the following:


  • Cost-Effectiveness: One of the most significant advantages of single cylinder deadbolts is their affordable price. That’s especially important if you intend to buy several locks for your home.
  • Convenient Use: The deadbolt requires a key only on the outside. Once inside your house, you only need to toggle the thumb-turn mechanism to lock and unlock it.
  • Great for Emergencies: Since it is easier to open from inside, single cylinder deadbolts make it possible to leave your house in an emergency quickly. There’s no need to look for misplaced keys.


  • Less Secure: Even though capable of providing a certain level of security, single-cylinder deadbolts can be less secure than their  double-cylinder counterparts.

What Is a Double Cylinder Deadbolt?

Unlike single-cylinder deadbolts, double cylinder deadbolts require a key to unlock and lock from either side of the door. A key is necessary to lock and unlock, whether inside or outside the house. Another significant difference with single-cylinder deadbolts is that it has no thumb-turn.

With a double-cylinder smart lock, it is no longer necessary to rekey a deadbolt to lock or unlock it. You can set the lock to work without rekeying once you have a functioning key, Kwikset key, and a SmartKey Learn Tool.

Pros And Cons of Double Cylinder Deadbolt

On a double-cylinder deadbolt, the two cylinders make a huge difference. Compared to single-cylinder deadbolts, double-cylinder locks come with several pros and cons, including the following:


  • Cost-Effectiveness:  A double-cylinder door lock is as affordable as its single-cylinder counterpart. The price difference depends on product brands and models and could be only a few dollars.
  • High-Level Security: You need a key to open the door from either side for a double-cylinder lock. With that, it enhances your home security by a great deal.
  • Protection for House Occupants: Double-cylinder locks effectively protect minors or aging adults inside the house. The lock can prevent this category of people from going outside anonymously.


  • Lacks Universality: Double-cylinder locks are not for use on all doors around your home. Therefore, they are unsuitable for instances when you want to utilize uniform deadbolts throughout your home.
  • Inconvenient: A double-cylinder deadbolt can be very inconvenient when the occupants of a house want to leave in a hurry. Unlike the single-cylinder lock, you must locate a key and use it to unlock the door before leaving the house.
  • Could be Illegal: The fire codes in some cities and states do not allow the use of double-cylinder locks on residences. For example, in San Jose, California, double-cylinder locks are illegal, while in Texas, they are legal.

Single Cylinder Vs Double Cylinder Deadbolt: What Are The Differences?

There are significant differences between single-cylinder deadbolts and double-cylinder deadbolts beyond their physical looks. The following are the distinguishing factors between these two types of deadbolts:

1. Number of Cylinders

While single cylinder deadbolts have only one cylinder, double-cylinder deadbolts have two. However, you can convert single-cylinder deadbolts to double-cylinder by removing the thumb-turn and installing and replacing it with a cylinder. Once you do that, you can open the lock from both sides.

2. Keyhole

Single cylinder deadbolts have only one keyhole outside, while double-cylinder deadbolts have two keyholes. That means that you can lock and unlock it using a key from outside and inside.

3. Thumb-Turn

Only single cylinder deadbolts have a thumb-turn for locking or unlocking it from the inside. That makes it convenient to open the lock when in an emergency. However, a double-cylinder deadbolt doesn’t have a thumb-turn. Opening it from either inside or outside requires a key.

4. Requirement for a Key

With single cylinder deadbolts, you need a key to lock and unlock it from the outside. Unlocking or locking the door from the outside requires a simple thumb-turn. On the other hand, a double-cylinder deadbolt requires locking or opening with keys from both sides.

5. Convenience

While single-cylinder and double-cylinder deadbolts are essential in providing security, they aren’t all convenient to use. Single-handle deadbolts – with a thumb-turn mechanism – are the most suitable for conveniently opening the door from the inside.

On the other hand, a double-handle deadbolt has no thumb-turn and can be inconvenient to open from inside when there’s an emergency.

Comparison Chart

AttributeSingle-Cylinder DeadboltsDouble-Cylinder Deadbolt
Number of cylindersOneTwo
Requirement for a keyOutsideInside and outside

Which Is Better Single Or Double Cylinder Deadbolt

Single-handle deadbolts are the best to buy when it comes to convenience of use. However, it might not provide adequate security. If you want to make your home more secure, you should purchase a double-cylinder deadbolt that requires a key to lock and unlock from both sides of the door, making it more secure.

Deadbolt pricing is not a significant issue when considering a single-cylinder or double-cylinder since both prices are nearly the same, with a few variations.


What questions do you have about single-cylinder and double-cylinder locks? Here is a sample of some of them and the appropriate answers:

Are double-cylinder deadbolts legal?

Double-cylinder locks are legal in most states. However, fire safety regulations in some cities illegalize double-cylinder locks because of how inconvenient they can be to open from inside. An example is the city of San Jose, California, where double-cylinder deadbolts are illegal.

Is it easier to pick single-cylinder deadbolts?

Yes and no. Due to the use of a single-cylinder, this type of deadbolt can be less secure than its double-cylinder counterpart. While it requires a key to open from the outside, the inside has a thumb-turn which you can use to lock and unlock.

Does double-locking make a difference?

Double locking makes a difference because it physically secures the latch, rendering it impossible to move. With double locking, your door is much more secure. Therefore, you are assured of more excellent safety.

What is a double-cylinder deadbolt?

A double-cylinder deadbolt is one with a key on either side of the door. You need a key to lock and unlock this type of deadbolt, whether outside or inside. Even though it is inconvenient to open a door from inside, it is very secure.


The importance of having a secure deadbolt cannot be gainsaid. It can stop intruders from raiding your home and stealing valuables. When considering a single-cylinder vs. double-cylinder deadbolt, it is essential to pay attention to functionality, security, and ease of opening.

Single cylinder deadbolts are more convenient to open from inside (due to the inclusion of a thumb-turn mechanism) than double-cylinder locks. However, if you want more security, a double-cylinder deadbolt is better. Pricing isn’t critical since the two types of locks tend to cost nearly the same.

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