Skip to Content

Types of Keys: What’s The Differences & When to Use Each

Types of Keys: What’s The Differences & When to Use Each

Keys first came into use in Egypt and ancient Babylon six thousand years ago. They continue to be the most commonly manufactured metal objects globally. 

Knowing the different types of keys can save you time and make your life easier as a homeowner.

Whether you’re looking for a key to fit in your front door lock or need to unlock a padlock on a storage unit, knowing what type of key will work best is essential.

Read on to learn more about the different types of keys that exist, where they fit, and more.

The Different Types of Keys

For a piece on the different types of keys, a bunch of keys sit on a yellow background in a layflat image

Sergio Rojo/Shutterstock

There are a variety of different keys that homeowners should become familiar with. To get the most out of your home, it’s a good idea to have an understanding of these types of keys and what they do.

The following information will help you understand how locks work in general and the specific type of key required for each lock.

There are two main types of keys: single-sided and double-sided keys. Let’s look at these before we delve into other diversified types of keys.

Single-Sided Keys

In a single-sided key, the profile on one side of the blade matches precisely with the corresponding biting on the other. The most common examples are keys used for padlocks or cabinet locksets.

So if you’re designing your home, you might want to make sure you have locks for your cabinets and doors that use single-sided keys. Single-sided keys usually have two slots cut into them to be inserted and rotated in either direction to open/unlock the lock.

When dealing with single-sided keys, it is essential to pay attention to which way they are inserted into the lock’s keyway because no two-biting cuts on one side will align perfectly with both slots of a double-sided key.

Double-Sided Keys

A double-sided key is also known as a “double bit” key, and it’s the most popular type of house or apartment key. Single-sided keys are not meant to be inserted into a double-keyway because they will only rotate in one direction (usually clockwise).

A double-sided key can be inserted either way without issue since there are two sets of biting cuts on one side of the key. Double-sided keys come in handy when looking for a lost key because homeowners can try both sides of the double-keyway to see if it fits.

There is no easy way to tell which side should be inserted first unless you get lucky with trial and error when inserting single-sided keys into double-keyways. When working on your home security, you should consider replacing the locks inside your home with double-sided deadbolts.

In addition to being more secure, they’re also easier for you and your family members to use because it’s impossible to insert a single-sided key backward into a double-keyway.

One shortcoming with double-sided keys is that you cannot tell which side the key is on just by looking at it. This means that you must always carry both keys with every double-keyway lock to ensure they work correctly and replace them as a set if one of them breaks or gets lost.

Other Types of Keys Used at Home

Various multi-color key blanks sit in a large pile to show how many different types of keys there are

Michael Smolkin/Shutterstock

Other types of keys used at home are classified based on how they’re made or cut, and further diversification. These types of keys include:

Mechanically Cut Keys

Mechanically cut keys are also known as change keys. They’re used to operate the locks in your home if you lose all of your keys

They operate by moving one tumbler at a time and will not work on either knobs or deadbolts.

Laser-Cut Keys

A laser-cut key is unique because it uses a machine to duplicate the original. It makes multiple passes over one tumbler, which will allow you to operate deadbolts and knobs in your home with no problem.

If you’re looking for a way to keep your home secure, but you don’t want anyone else to gain entry into it without the correct key, then an electronically cut key is what you need.

You can use this type of key on both knobs and deadbolts. However, if this option does not fit within your budget, there are still other ways to ensure your home is safe without spending too much.

Blank Keys

A blank key is a key that hasn’t been cut into its shape yet, but you can use it on locks with the same type of key. This means if you have a standard lock, then there will be several blanks available for purchase that you can use to unlock it.

Locksmiths mainly purchase blank keys, so they’ve got various types on hand at any given time. This is useful if someone needs to get into their home quickly and cannot wait until the correct key is made.

If you’re looking to replace all of your locks for security reasons, this can be the most expensive option since each key type needs a different blank. However, if you only need one or two keys that can open multiple locks, it may work out in your favor financially.

Commercial Keys

Commercial keys are a universal type that can open a variety of different locks. They work by having the grooves on one side fit into the wards of a lock while the top part with notches or teeth slides in from the other side to catch them and turn.

It would be best to use this option only if you’ve got your landlord’s permission to change the locks on your rental unit. Only remove one lock at a time to avoid lockout issues, and go for simpler options when possible.

Keyed Alike

This option is exactly what it sounds like. If you want multiple locks operated by the same key, this will be your best bet, as each lock will need its own unique code or number of cuts or knots on the blade.

This way, they can’t all turn with one universal key, and this option is great for homeowners who want to use the same key on all of their exterior doors.

Frequently Asked Questions

Small mailbox keys sit on a dark wooden table to illustrate unique types of keys


What are the main types of key-operated locks?

There are four types of locks that a key can open. These include deadbolts, knob sets, levers, and rim cylinders. Deadbolts are the highest security level and are best for exterior doors.

Knob sets have a lock that is turned by turning the door handle. On the other hand, Levers work in much of the same way but instead use a traditional locking mechanism where you push down to open/close the door.

Finally, rim cylinders require less maintenance than locksets with other mechanisms, as you can open them with a key from the outside only.

Are all lock keys the same?

The short answer is no! There are various locks and key types, including Keyed Alike, Master Key, and High-Security Locks. All locks have different types of keys except for Keyed Alike locks that have the same key.

Is it possible to change keys without changing locks?

Many homeowners are under the impression that they can change keys without changing their locks.

Unfortunately, this is impossible because each key has a unique code that only works with specific lock combinations. This means if you’ve to replace your lock, it will be necessary to purchase new matching locks for every individual key in use.

Choose the Best Key from these Types of Keys

Do you want to choose the best key that suits your requirements and can be used in most locks? Before buying a new lock, you should always check with the manufacturer of your current system for compatibility issues.

Taking time to choose the best lock and key can go a long way toward maintaining your home’s security and saving you a lot of money and time. Choose wisely!