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Single vs Double Cylinder Deadbolt: Similarities & Differences

Fact checked by Teddy B.Miller

single vs double cylinder deadbolt

Planning to add extra security to your home or business space? Pay some attention to the locking mechanism on doors and the deadbolt. Deadbolts provide an additional layer of protection by offering better resistance against forced entry attempts.

Exploring the available deadbolt lock options will likely land you on two popular types: “single cylinder” and “double cylinder”. So, single vs double cylinder deadbolts, what are the differences?

In this article, we will delve into the two deadbolt options, pinpointing the characteristics, advantages, and further information to help you make an informed decision and reinforce the safety of your home.

Single and Double Cylinder Deadbolt Definition

First, let’s go over the basics!

1. Single cylinder deadbolt


So what is a single-cylinder deadbolt? A single-cylinder deadbolt is one of the two types of deadbolts that is used as a lock mechanism in doors that utilizes only one cylinder to either lock or unlock the deadbolt.

A single-cylinder deadbolt is a type of door lock that operates with a key on the outside and a thumb turn on the inside.

The key cylinder is located on the exterior side of the door. It allows access as well as locks and unlocks the deadbolt from outside. On the interior side, a thumb-turn mechanism is designed for easy locking and unlocking without needing a key.

The single-cylinder deadbolt locks are convenient for everyday use. They also provide extra safety with the exterior lock. That’s why single-cylinder deadlock is widely used for residential properties.

2. What is a double cylinder lock?


Derived from its name, a double cylinder deadbolt is one of the two types of deadbolt locks which is used to lock a door that utilizes two cylinders on each side of the door to either lock or unlock the door.

A double-cylinder lock requires a key for both the exterior and interior sides of the door to operate the lock. This prevents unauthorized access from either side of the door. Without a designated key, intruders cannot gain access to the property, even when they break nearby glass panels and try to manipulate the lock.

Double cylinder deadbolts are commonly found in commercial buildings where security is prioritized rather than convenience.

How Do They Work?

1. Single cylinder deadbolt


A single cylinder deadbolt lock consists of two main components: the key cylinder and the thumb turn mechanism. Here’s how they work:

  • From outside of the door: On the exterior, a key must be inserted into the key cylinder and turned in the appropriate direction to lock or unlock the deadbolt.
  • From inside of the door: On the inside of the door, there’s only a thumb turn mechanism. By rotating the thumb turn, the deadbolt is engaged or disengaged, which locks and unlocks the door without needing a key.

2. Double cylinder deadbolt


For doors that use the double cylinder deadbolt lock, accessing from both inside and outside of the door requires a key. The key cylinder works the same as that on a single cylinder lock but in double the number. 

Both of these deadbolts are usually paired with a handle to easily push or pull the door.

What Are Their Differences?


Both the single-cylinder and the double-cylinder deadbolt locks have a key slot on one side. However, the single-cylinder deadbolt has a thumb turn on the other side, while the double-cylinder has another key slot.

Because of this difference, the single cylinder is regarded as more convenient but less secure, while the double cylinder is less convenient but more secure.

  Accessibility Security Price
Single Cylinder Deadbolt Convenient for day-to-day access Less secure than the double cylinder deadbolt Cheaper than door knobs
Double Cylinder Deadbolt Inconvenient for universal use More secure than the single cylinder deadbolt More expensive than single cylinder deadbolt

Single Cylinder vs. Double Cylinder Deadbolts: Pros and Cons

1. Single-cylinder deadbolt

If you are looking to install a single-cylinder deadbolt, check out these pros and cons first.

  • The price of single-cylinder deadbolts is cheap and low compared to door knobs
  • Accessing is convenient
  • Less secure compared to double-cylinder deadbolts

2. Double-cylinder door lock

  • Way more secure than single-cylinder deadbolts
  • Can keep occupants from leaving the room easily
  • The price of double-cylinder deadbolts is cheap
  • Difficult to access, especially in emergencies
  • Inconvenient for universal use
  • Illegal to install in some states due to fire codes

How Much Do They Cost?

A single-cylinder deadbolt costs around $20 – $70, while double-cylinder deadbolts would set you back around $15 – $115 depending on the model and make of the deadbolt.

Which One is Better?


There is no clear-cut answer for which is better, single cylinder deadbolt vs double cylinder deadbolt. The best option depends on the situation as well as the security needs of property owners.

To limit the chance of burglary, you may want to install a double-cylinder deadbolt. It will make your home or business more secure. Double-cylinder deadbolts are also preferred if you have children you don’t want to go outside accidentally.

A single-cylinder deadbolt is suitable for most residential purposes. In case of fire hazards, you can always have easy access to your door. If you want convenience, the single-cylinder deadbolt is the way to go.

Single-Cylinder Deadbolt vs. Double-Cylinder Deadbolt: Factors to Consider


Each type of deadbolt will shine depending on the situation and your security needs. Here are some factors you should be considering when choosing between single and double-cylinder deadbolts:

  • Location of Use: A single-cylinder deadbolt is better for areas prone to fire, while a double-cylinder deadbolt works best for places with high crime rates. Also, installing a double-cylinder deadbolt may be illegal in your state. Be sure to check with the authorities first.
  • Commercial or Residential: Double-cylinder deadbolts are generally better for securing your business, while single-cylinder deadbolts are more family-friendly.
  • Family or Living Alone: A single-cylinder deadbolt is better if you have a family. A double-cylinder deadbolt would be safer and more secure if you lived alone.

Installation and Maintenance


The installation process of the single and double-cylinder deadbolts is the same.

First, install the deadbolt mechanism, and the strike plate, check the alignment, and finally, add the door handles if necessary.

If you want to convert a double-cylinder deadbolt to a single-cylinder, it would be relatively easy.

Maintenance for single-cylinder deadbolts, however, would take much more lubrication since the thumb-turn can get stuck due to wear and tear. You should also regularly clean your dual cylinder lock since dirt may accumulate in keyways that inhibit the key from turning.

Frequently Asked Questions


Are single-cylinder deadbolts easier to install than double-cylinder deadbolts?

No. Both of these types have the same installation process. It would take similar efforts to install either type of deadbolt. 

Can I use a smart lock instead of a single or double-cylinder deadbolt?

If you want convenience when accessing your doors, you can always use a smart lock instead of having a single or double-cylinder deadbolts. Opting for a smart lock would cost around $100 – $250, compared to the range of deadbolt prices, which is $30 – $50.

Are double-cylinder deadbolts legal?

It depends. There are rules and regulations that differ between states and are applied to varied situations.

For example, double cylinder deadbolts can be installed without legal punishments for existing homes, in Minnesota. However, in the same state, if you are going to put up a new house, you should not install a double-keyed deadbolt, according to the Residential Building Code.

We advise homeowners or property owners to comply with local regulations and ensure the safety of occupants. Consult with professionals or local building code officials to make informed decisions that suit your situation.


When it comes to your family’s safety, valuables, and yourself, you should consider what is best to protect them.

Knowing the difference between single vs double cylinder deadbolts not only improves your handiness knowledge, but it will also help you design and plan out your security system for your house and for your business.

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