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Everything You Should Know About Master Keys

If you have ever asked yourself how can just one key open several doors, read on. Our pros have compiled a comprehensive guide on master keys. At the end of this article, you will know what is a master key, what are the pros and cons of master keys, and whether these options are suitable for everyone.

What Is A Master Key and How Does It Work?

Some lock models are designed to work with two completely different keys. A change key can be used to exclusively open a specific lock, while a master key will be used to open the respective lock as well as several other locks part of the same group. For the locks part of the group, some of the pin pairs are separated by a third pin. The latter is called the master wafer or master spacer.

Once three pins are mixed inside the shaft, the pins can be positioned in two of two ways to open the lock. For the change key, the pins might go up in order for the shear line to reach the position just above the top of the master wafer. When the master key is used, it might work by raising the pins in order for the shear line to reach the bottom of the master wafer. In both scenarios, is a gap at the shear line and the key is able to turn. In both scenarios, a gap will be formed at the shear line, causing the key to turn in the lock.

For master key designs, the lowest pin must have the same length in each lock part of the group. However, the master wafer will have different lengths. This will enable the holder of the master key to get access to any lock part of the group. A person with a change key will solely be able to open their own lock.master key systems

Master Key VS Keyed Alike Systems

Many people confuse keyed alike (KA) locks with master keyed locks. Keyed alike systems are sets of locks that can be opened using the same key. All locks in the set are clones of one another and they have the same set of pins and levers. A keyed alike lock can only be opened by a single key or its copy.

While similar, master key systems refer to sets of locks that can all be opened by both a master key and a separate key.

Does the Master Key System Really Work for Everyone?

The short answer is no. Master key systems, which are key plans that allow specific keys to open a certain number of doors, are suitable for certain categories of users. This includes building supervisors and landlords, and managers of business buildings, schools, hospitals, or hotels. However, there are also plenty of situations when these keys would not serve their purpose efficiently or when losing them might become a serious problem. Here is what you need to know:

Buildings with custodial staff

As a general rule of thumb, buildings with custodial staff make for good candidates for master key locking systems. In case of an emergency eviction scenario when the tenant has suddenly left without a warning, locking the door behind, and taking the key without permission, a master key will grant access to the apartment.

With the same master key model, a school or hotel janitor will not be forced to carry a heavy ring with a large number of keys. Instead, they can limit the number to just two or even one key and save precious time searching for the right key every time.

Business managers

Business managers who are in charge of dozens of offices and rooms with different purposes inside the same building will also find a lot of purpose in using complex master keys with different levels of access granted to different types of employees and staff members for enhanced access control.


Homeowners, on the other hand, may not gather as many reasons to opt for a master key to the detriment of a standard key or a smart lock ensemble. While for some people master keys might prove to be helpful to some extent, they are not actually necessary. This is particularly true for those homes with a small number of doors where having just one key for each door is not worth the price.

Master Key Pros and Cons

We have listed the main benefits and drawbacks of master key systems:

Master Key System Pros

Better key management. Managing, storing, and safeguarding a large number of metal keys can be a real struggle. Keys oftentimes get lost, misplaced, stolen, or they break because of wear and tear. With a master key system, there is no need to worry about keeping track of more than one key.

Superior access control. Building managers or owners can easily designate various levels of masters based on access needs and level of employees and allow multi-level access while preventing unauthorized access and theft.

Affordability. Master key systems have convenient prices and they are easy to use. This means they are an affordable and flexible security measure that can eliminate the need to use multiple locks or additional security devices.

Quick records for re-keying. These systems also keep records of all levels of accessibility and masters. In case of an emergency, professional locksmiths can rapidly rekey any lock and restore your security.

Master Key System Cons

The biggest drawback is that lost or stolen master keys do not benefit from any additional security. Anyone who finds them can freely enter the premises. Also, lost master keys that require replacement may incur higher prices.

Finally, similar to standard keys, most master keys can be copied. However, restricted or registered master keys cannot be duplicated, as they require key authorization from the building’s owner.

For professional master key services including planning and upgrades, get in touch with our expert locksmiths to benefit from quality options at affordable prices.