Home Security and Safety Tips

Different Types of Door Locks – a Fantastic Guide (+ Illustrations)

The safety of our homes and families is more than likely a priority for every one of us. And the locks we put on our doors are the first line of defence against intruders. So, it comes as no surprise that if our door locks are old, malfunctioning, or just ineffective, we’d want to upgrade to a better, more secure model.

But how are you supposed to know which lock is right for you? There are so many options out there! Don’t worry – in this post, we will go over the most common types of door locks and hopefully give you all the information you need to make the right choice.

Table of Contents:

So, if you:

  • Are thinking of changing your locks;
  • Want to find out more about the various types of door locks;
  • Are wondering “What type of door lock do I have?”,

Then look no further, because this post has the answers!

What are the different types of door locks?

While there are numerous types of door locks on the market, here, we will talk about the most commonly used ones. So, let’s get started!

Mortice deadlocks

Now, what is a mortice lock exactly? Well, it’s a style of door lock that requires the installer to cut a cavity, called a ‘mortice’, into the door frame. This opening is where the lock is then fitted, followed by a strike plate.

If you’re looking for a less visible lock, then the mortice lock is the one for you, as most of the mechanism is hidden inside the door itself. This not only makes them more visually appealing but more secure, too.

A mortice deadlock can be locked and unlocked with a key from both sides. They are an excellent option for people who don’t want to deal with too many sets of keys, as they can be keyed alike. This means that you can unlock several mortice locks with the same key.

Mortice deadlocks are most commonly found on front and back doors, and rarely on internal ones.

There are a few different types of mortice locks, but the 5-lever one is by far the most preferred.

5-lever mortice deadlocks

This is perhaps the most common type of lock, and with good reason.

But what does ‘5-lever’ mean? Well, as you can probably guess, it stands for the number of levers the key has to move to slide the deadlock back. Naturally, the more levers the lock has, the more secure it’s considered to be.

So, you might be asking yourself “How do I know if my lock is a 5-lever mortice deadlock?”. It’s quite simple, really.

The first sign that you may have this type of lock is if you have a wooden door. You won’t find a 5-lever mortice deadlock on composite and uPVC doors, so if that’s what you have, then there’s a different type of lock fitted.

If the lock mechanism is fitted into the edge of the door, as opposed to the surface, then yes – it’s a mortice lock.

And last but not least, take a look at the faceplate of the lock, where you should find the number of levers stamped on. If the faceplate says “5 LEVER”, then you know your locking mechanism is a 5-lever mortice deadlock.

What if you want to boost security even more, though? Well then, this is where the BS3621 lock comes into play.

BS3621 5-lever mortice deadlocks

This type of door lock works in the same way as the 5-lever mortice deadlock; however, it conforms to the British Standard BS3621. This means it’s been tested against various burglary methods, making it more secure.

But how can you identify it?

A 5-lever mortice deadlock conforming to BS3621 should have the British Standard Kitemark engraved on the lock’s faceplate. Again, the number of levers will also be engraved, as will the standard number.

So, let’s move on to the next door lock type.

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Multi-point locking systems

A multi-point locking system does precisely what the name says – it’s a key-operated mechanism that locks into the door frame at multiple points, most commonly varying from 3 to 5. This makes it more secure, as the numerous locking points make it harder to force the door open. However, as it’s only one lock on the door, it’s not impenetrable, as the burglars will only have a single lock to pick.

This door lock type is fitted into the door itself, much like the mortice lock. However, you can commonly find them on uPVC and composite doors. They can also be fitted to timber and aluminium doors, as well as French and Patio ones.

Usually, multi-point locking systems are operated by a euro cylinder lock (more on that below). You only need one cylinder to lock the door at all the points simultaneously. However, if you’re not sure how to use the system properly, you might not lock the door entirely, leaving it vulnerable to attacks.

Like the mortice lock, you can key this type of door lock alike, letting you use a single key for all your external doors.

Most commonly, you can find this lock type on external front and back doors.

Rim automatic deadlatches with key-locking handles

With this type of lock, a nightlatch is placed on the inside of the door, and the key-operated cylinder goes on the outside. Usually, this type is used as a secondary security measure and won’t be the only lock you have.

It’s pretty straightforward to use – it’s opened by a key on both sides of the door and locks automatically once shut.

The difference here is that this is a rim locking mechanism, meaning it’s fitted on the surface of the door, as opposed to inside the door edge like the mortice lock.

You’ll usually see this door lock type on front and back doors.

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Cylinder locks

Lots of different lock types, such as the multi-point locking system, use the cylinder locking mechanism, also known as a pin tumbler lock.

A cylinder lock uses pins of varying lengths. The key must move them into the right position for you to be able to turn it and unlock the door. As convenient as they are, however, cylinder locks are prone to lock snapping and other burglary techniques if not fitted correctly.

There are three locking types – single-cylinder, double cylinder, and thumb turn. You can only lock single-cylinder locks from one side; double-cylinder ones lock from both sides; thumb turn kinds lock with a key from the outside and a thumb turn lock on the inside.

You can find this type of door lock on external doors, as well as internal ones, though not as often.

There are two main types of cylinder locks – euro and oval.

  • Euro cylinder locks
    This is one of the most commonly used locking mechanisms in modern homes. It is shaped like an enlarged keyhole. Unfortunately, the standard lock composition makes it prone to snapping in the middle. Because of this, manufacturers have created anti-snap versions that snap at the end, preventing the lock from being manipulated once snapped.
  • Oval cylinder locks
    The main difference between euro and oval locks is the shape – oval ones are, naturally, oval-shaped. They’re commonly used with oval mortice lock cases. Oval cylinder locks are mostly double-cylinder. As these are less popular than the euro varieties, there are fewer sizes and brands to choose from, and thumb turn mechanisms are usually not used with this design.

And, speaking of…

Thumb turn locks

This is a very basic locking mechanism. The bolt moves when the thumb turn lock is turned, and there is no need for a key. In case of an emergency, you can open the door from the outside with a coin.

You’ll usually find this type of door lock on bathroom doors. And if you don’t have one, check our post on how do you install a thumb lock in a bathroom.

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Need help choosing and installing a door lock?

If you’re not sure which lock is right for you, why not call the experts at Fantastic Services? We offer a professional lock replacement and installation service that is sure to make your home feel as safe as possible. With fully insured technicians, BS3621-compliant locks, and a 6-month guarantee on all the work done, Fantastic Services is without a doubt the way to go! And, if you want to know more about what the locksmith service can cost you, check out our helpful post!

So, book your lock installation today using our simple booking form and ensure the security of your home and family!

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  • Mortice deadlocks are one of the more secure options on the market and are fitted inside the body of the door.
  • Multi-point locking systems lock at several points, making them a good preventative measure against intruders who might try to force the door open.
  • Rim automatic deadlatches with key-locking handles are fitted on the surface of the door and are usually a secondary security measure.
  • Cylinder locking mechanisms are used in a wide variety of locks, with the euro-cylinder lock being the preferred kind.
  • Thumb turn locks are usually found on bathroom doors.
  • Nightlatches can lock the door automatically and are opened with a key from the outside and a knob from the inside.


Was this post useful to you? Do you have any additional questions or interesting facts about the different types of door locks? Let us know in the comments!

Image source: Polly Ivanova Illustration

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