Last updated: August 9, 2021

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According to the exact definition, a door lock is a mortise lock for the door and represents a mechanical locking of the doors, it locks the door to the door frame. However, in a colloquial sense, door locks also include the profile locking cylinder and other locking options.

In this article, you will find all the important information and advice as well as recommendations on the individual products related to the topic of door locks. For our comparison of the products, we have compared various models with each other and explained the most important aspects.


  • Door locks are used to lock doors. For interior doors, often only buntbart locks with a very low security level are used; for exterior doors, however, a lock with a high security level should be selected; here, profile cylinders are used.
  • In the colloquial sense, a distinction is made between mortise locks, profile cylinders and electric locks. All variants are available in different price classes.
  • Depending on the area of application, there are a wide variety of locks with significant differences in terms of their security and the built-in protection devices.

The Best Door Lock: Our Choices

Buying and evaluation criteria for door locks

If you want to buy a door lock, the purchase decision can be very difficult due to the large number of models. In the following, we show you which aspects and criteria you should consider when choosing the right door lock.

Here we present 6 criteria to help you decide between the individual models:

Number of keys

The number of keys for most door locks is between 1 and 5 per lock. It depends on how many people in your household or locking system need a key. In most cases, keys can be easily reordered by means of a copy of the existing key or by means of a key card which is enclosed with some offers. With this card, a key with the code on it can be duplicated by the key manufacturer or locksmith.

If you need significantly more keys, an electronic door lock variant is a great advantage, as depending on the product, up to 999 users can be stored here and these are also easy to manage. You can set access authorisation via an app.


There are several dimensions for mortise locks that you need to consider:

  • Backset: The backset describes the distance from the outer edge of the door to the centre of the lock cylinder.
  • Mortisedepth: The mortise depth stands for the total depth of the mortise lock from the outer edge of the door to the maximum milled point inside the door.
  • Square dimension: For the square dimension, the diameter of the handle set must be measured; in most cases this is 8-10 mm
  • Distance between latch and deadbolt: The distance between the latch and the deadbolt is measured here, this must match the notches in the door frame.
  • Forend dimension: The forend dimension describes the intermediate dimension of the two screw points of the mortise lock for connecting to the door.

For a lock cylinder, however, there are primarily only 2 dimensions - the rest are standardised. These are the inner and outer dimensions measured to the centre of the cylinder to which the lock is screwed. For example, 30/45 means 30 mm from one side of the lock and 45 mm from the other to the centre. You must measure this on your existing door, ideally the lock cylinder should not protrude here.

Picking protection

Picking protection is a device that prevents a lock from being picked with a picking tool. The bolts can no longer be brought into the correct position by the tool in order to then turn the locking cylinder and open the door. This protection device can be chosen as an extended protection for profile cylinders, especially for front doors.

Material quality

A classic lock cylinder is made of a brass alloy and is then usually coated with a nickel alloy. Normal steel is used inside the lock, but in high-quality and secure locks, hardened steel is used for the bolts inside the lock cylinder to make the lock more resistant to drilling.

Security level

Depending on the manufacturer, profile cylinders are divided into different security levels, ranging from the simplest security level with standard drilling protection to high-security locking cylinders with increased drilling and pulling protection as well as picking protection.

Guide: Frequently asked questions about door locks

In the following, we would like to answer the most important questions on the subject of door locks in brief. After you have read through the guide, you will have the most important basic information on door locks.

What types of door locks are there?

Mortise locks are available with a buntbart lock or with a device for other cylinders, these are available in many different sizes and designs. Furthermore, a distinction is made between normal profile cylinders, knob cylinders and electronic door locks. Each has its own advantages.

  • Mortise lock: The mortise lock is required as a device for fitting all the variants of locks listed below in the door.
  • Buntbart lock: A buntbart lock is used indoors for room doors or barns and has a low security level. A multi-part lock is not retrofitted in the mortise lock as is the case with the other following locks, but is prefabricated in the mortise lock if you choose this variant.
  • Profile cylinder: This is mainly used for flat doors, front doors and other entrance doors; it is available in different security classes and with different key variants.
  • Knob cylinder: A knob cylinder is a profile cylinder with a knob that is located inside the house; with the help of the knob, the lock can be operated without a key. However, it can be opened from the outside with a normal key.
  • Electronic door locks: Electronic door locks are available with app control or fingerprint sensor, often also with remote control or Bluetooth or WLAN connection. The advantage is that no key can be lost and a large number of locking authorisations can be set up.

Which door lock is right for you depends on which object you want to lock and which additional features the door lock should have.

What does a door lock cost?

The price varies depending on the model and design. The following table will give you an overview of the prices of the individual models.
Type price
Mortise lock approx. 6 to 25 euros
Buntbart lock approx. 6 to 25 euros
Profile cylinder approx. 8 to 250 euros
Knob cylinder approx. 15 to 250 euros
Electronic door lock approx. 80 to 1500 euros

As you can easily see, the range for the individual variants is very high, as there are many different security classes and designs.

How do I change a door lock?

When replacing a door lock, the profile cylinder must first be unscrewed; it is only fixed with one screw, which is located on the side of the mortise lock under the bolt and thus above the lower screw of the faceplate.

There are usually only 3 screws on the mortise lock and the middle one is the one for the profile cylinder. Unscrew this screw completely and then turn the door key by about 20 degrees to unlock the lock and remove the profile cylinder.


To remove the profile cylinder, you have to turn the key to a position of about 20 degrees to release the lock. (Image source: unsplash / multifacetedgirl)

The mortise lock itself is fastened to the forend with two screws; if you unscrew these, you can already pull out the mortise lock.

Then you can take all the relevant measurements, depending on whether you want to change the mortise lock or the profile cylinder, to find a suitable new door lock.

You can find out which dimensions are necessary in one of the previous chapters under "Dimensions".


In conclusion, door locks are an important product for domestic security, both indoors and outdoors. Door locks are available in a wide range of security classes and are suitable for a wide range of requirements. Installation is usually not difficult and can be done with a screwdriver.

Regardless of whether you need 1 to 5 keys or even want to set up up to 1000 locking authorisations for electric door locks, there are all kinds of options for door locks, even entry via fingerprint sensor or app control is possible.

Image source: pixabay / neshom

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