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Create your master key system

As professional locksmiths, we pride ourselves on providing the best security solutions for your residential, commercial, and industrial properties, including the design and implementation of a master key system.

Keys and locks have been used for centuries to prevent unauthorised access and, although still widely used, they come with their fair share of risks.

For starters, key management can become a hassle. Since one key opens one specific door only, you can end up with hundreds of different keys, especially for large residential complexes and commercial buildings.

They can become extremely challenging to keep safe and you may lose or misplace some and some might get stolen. In addition to that, searching for the right key in a giant keyring can be highly inefficient.

That being said, you must keep in mind that a compromised key equals compromised security since whoever has the key, has access to your property.

The solution to this pressing issue is a master key system that reduces the number of keys and lets you manage them in a way to prevent unauthorised access and allow only authorised individuals through specific entry points.

Read on to find out what master key systems are, how they are designed, what to consider when creating one, along with their benefits to property owners:


Master key systems have become fairly common among property owners since they significantly increase control and improve security.

Under this keying system, you can use a single lock to open different locks within a building. It is highly customisable and can be changed and adjusted according to your safety requirements.

It is a secure keying solution that uses the pin-and-tumbler design at its core to allow selected keys to open a selected set of locks.

A master key system is an ideal solution for all types of buildings, especially ones that have several access points and can benefit from the added security from the system.

For medical facilities, such as hospitals with lots of employees and data, tools, and machinery, a master key system can be a good step towards strengthening security and access control.

Similarly, educational institutions such as schools, colleges, and universities, can benefit from a master key system by allowing the head of the institution access to every room and the staff to certain classrooms only.

Other properties include offices, banks, warehouses, and factories, all of which house valuable items and confidential information that must be kept safe from unauthorised individuals.

Let’s take a school building as an example. A school building can have a master key that can open all the classroom doors. These classroom doors can also be opened by a key specific to each door, which could also open a closet inside the classroom, if there is one.

In other words, in a master key system, a single key can open several locks on the property if the locks are keyed alike.

If this school is part of several different school buildings with a single master key system, there may be a Great Grand Master key that would open the main entrance doors to the campus, as well as the classroom doors and closets.

The top-level key in a master key system, also referred to as the Great Grand Master key, is able to access all the doors on the property, even though each lock has its own unique key as well.

Therefore, a master key system can be designed along different sites and departments to allow and control access throughout the property.

The next level in a master key system, called a Grand Master key, can open only designated doors, while change keys, or regular keys, can open only one door or room.


To design a master key system, you need to create a master key schematic, which is a blueprint detailing the building’s security.

Similar to an architect’s drawing, it translates the idea of allowing and restricting access into a property on paper, and any system with different levels of access must be tailored to fit the security needs of the building.

Before we dive into designing a master key system, it is important to understand the different types of keys that make up the system.

  • Change keys: also referred to as sub-master keys, open one lock only and locks that are the same. Any locks that can be opened by change keys can also be accessed through master keys and other keys above that level.
  • Master keys (MK): without the use of a master key, there is a single key for every lock. It is necessary to change a simple lock into a master-keyed lock, and the master key will often be the highest-ranking key in some systems.
  • Grand Master keys (GMK): a grand master key is a level above master keys and can be used to access several master key systems. It will open all the master key systems under it, as well as all the change keys under those systems.
  • Great Grand Master Keys (GGMK): the great grand master key is the key of the highest order and will open all the grand master systems under it, the master key systems under those, and the change keys under those.

A hierarchical diagram resembling a corporation’s organisational chart is prepared that communicates which keys will open which locks, or set of locks. Symbols and abbreviations are used, for example, GGM for great grand master key and MK for master key.

This layout is used to communicate how the keying system will be used and, once approved, the key codes are recorded, the cylinders are keyed, and the keys are cut.

A master key system is used in private homes and small to medium-sized businesses, where access is often restricted to a certain number of individuals.

It allows access to every cylinder within the system, which can be extremely convenient for managers and other executives who require access to all areas of the property. For added convenience, a master key system can also include furniture locks and other application locks.

A grand master key system, on the other hand, is mostly used in large organisations with a clear and well-defined structure.

The head of departments and the managers, who are on the top level of the system, may require unrestricted access to several areas of the building. Middle management may require access to certain areas only, whereas bottom level employees may most likely need access to only their particular working area.


When creating a master key system, there are a few important points to consider to make sure the system is a secure and efficient one.

By taking your time to carefully plan your master key system, you can increase the chances of having a highly efficient and effective system in place that perfectly balances security and convenience.

As a property owner or manager, you need to have complete access to all the entry points while authorising or restricting access for others based on their access permissions.

A master key system provides layered access to the doors across the property, and while it gives you added control and convenience when it comes to key management and security, it can also create a security risk if not implemented properly.

The planning phase starts with understanding that security and convenience are opposing forces: the more secure a system is, the less convenient it will be, and vice versa. Your target when creating your master key system is to strike a balance between the two.

When designing a successful master key system, make sure to structure the plan around your property and not the personnel. Focus more on the building areas than the job titles.

You may begin with a simple schematic that resembles an organisational chart and define the buildings, departments, and geographic areas. Make sure to include areas such as the stairwells, mechanical rooms, and HVAC areas.

Define your security objectives

Any security-related plan starts with defining what your security objectives are. You need to come up with a plan that allows you to balance both security and convenience.

As a best practice, it is often recommended to focus more on security than convenience, but luckily, with modern security systems, you don’t have to ignore the latter since they are designed to keep user experience and convenience in mind.

Determine the level of master key system needed

As mentioned above, there are different levels of master key systems and you need to determine which one your property requires.

Think of these levels as the levels of authority within the organisation, and the number of levels will depend on the building’s complexity and the number of people in it.

Your property may require a simple two-level system with change keys and master keys, a three-level system with change keys, master keys, and grand master keys, or more complex four-level systems with change keys, master keys, grand master keys, and great grand master keys.

Assign key symbols

You may use alpha, numeric, or alphanumeric symbols to identify the correct key combination with a door or group of doors.

For security purposes, master key system charts use blind codes to identify change keys and master keys.

To cut them, a locksmith uses a chart or computer program to translate the blind code into a bitting code, which is used in conjunction with the key’s depth and spacing to determine its unique geometry.


When implementing a master key system, you need to make sure that the keys are limited only to the people who are authorised to use them, they must not be duplicable, and must follow secure key control practices such as serial numbering and key tracking.

Preventing duplication

Master keys can be used to access all the doors within a property, which means that whoever has access to them has access to the doors as well.

Luckily, if someone attempts to copy them, they will be prevented from doing so since they are created on a restricted keyway which requires proper authorisation for key duplication.

Guaranteeing key security

Since master keys are authorised to access several doors and areas within a property, they must be secured in every way possible.

With the help of professional locksmiths, such as Calder Security, you can secure the condition and ownership of master keys by using unique serial numbers.

These serial numbers hold valuable information such as the identity of the key owners and the doors and locks that the keys can access. This information is tracked at all times to make sure that the keys remain only with their actual owners.

Key tracking

A great and notable feature of some master key systems is that the keys can be tracked at all times for better control and management.

Most of the time, this is achieved through computer software that is secured from online threats and gives property owners the control to effectively and remotely secure their properties from absolutely anywhere in the world.


A master key system is a great option for you if you wish to optimise your property’s safety and security. There are several benefits of using a master key system, such as:

Maximised control

One of the main benefits of a master key system is the level of control that it gives you. You, being the property owner or manager, have full control over who can access which areas of your property.

You may keep the master key all to yourself and use it to access all the doors on your property and give the rest of the building occupants keys to only certain areas while restricting access to others.

Trackable system

Another benefit of a master key system is the ability to manage and track the keys using key control software.

This allows you to digitally track who has which key, and access to which door. In addition to that, in case of a security incident, the system also allows you to track where the key currently is and when it was last used.


Cost-effectiveness is another reason you should invest in a master key system. The total cost of the system depends on several factors but, compared to an electronic access control system, it is much cheaper.

You need to keep in mind though, that the master key system being cheaper does not mean it is not reliable or secure.

Regarded as one of the best access control systems, considering all the necessary security measures and best practices have been adopted, a master key system is a great choice for residential, commercial, and industrial properties looking to maximise security.


Calder Security has been in the security industry since 1976 and we are members of the Master Locksmith Association (MLA).

We provide all kinds of security solutions designed bespoke to your property’s requirements and are experts in both master key systems as well as electronic and keyless access control systems.

Our expert team of SSAIB approved installers can help you assess your security needs and offer the right master key system or different types of access control systems including intercom, proximity fob, card swipe, keypad, and biometric systems that work with fingerprints or retina scans.

We are experienced with creating sophisticated access control systems for residential properties, large scale commercial enterprises, as well as smaller businesses.

We offer expert key cutting services from our Lock and Safe Shop in Wakefield where you can get your keys cut while you wait. We can cut virtually any key to a high degree of accuracy without having to send them away to be cut using our state-of-the-art digital equipment and key cutting machinery.

We can also work on a wide range of locking mechanisms, are specialists in wooden, UPVC, and aluminium doors, and the official suppliers for leading lock brands including Chubb, Yale, Securikey, and Garrison.

Contact us here or call us on 0800 612 9799 to talk to our professional locksmiths right away!

Photo by Jaye Haych on Unsplash