16 Types of Keys for Locks and Their Uses

If you’re like most people, you don’t give a lot of thought to keys in general. However, you most likely use several types of keys every day. Think about it, you have a house key, car key, and probably a key for work or something else around your home, like a greenhouse or shed. These tiny items that we don’t give a lot of thought to are what we trust to protect our items and our loved ones from intruders.

However, since we don’t think about keys much, it’s not uncommon that you don’t know that there are several types of keys available. It’s important to know at least the most common types of keys, and we’re going to outline them for you. This way, you’ll know exactly what key you need when it’s time to add or upgrade your locks.

1 Multiple Keys
If you look at your key ring, you may have different types of keys on it. This is very common because newer car keys look different from traditional house keys. Keys by chrisinphilly5448 / CC BY-SA 2.0

A Brief History of Types of Keys

Keys have a history that dates back 6,000 years to Ancient Egypt and Babylon, and this was the first time locks got invented too. Their keys were tooth-shaped, wooden, and very bulky or heavy. These types of keys functioned to lift tiny pins that were hidden in small openings next to bolts. In Ancient Rome, the key design was improved upon, and they worked to make them lighter, smaller, and stronger than wood using bronze or iron in the makeup.

This was the norm for a while before the flat, large keys were replaced by Skeleton Keys. These types of keys had a single, rectangular tooth with a cylindrical shaft. This key survived when the Roman Empire fell without a lot of changes, and they’re still popular if you have a home that was built before the 1940s.

Linus Yale, Sr. was an American mechanical engineer who introduced the more modern flat key design in the middle of the 1800s with his son. Since these keys were so easy to mass-produce, they quickly gained in popularity. We want you to learn more about the different types of keys, so we invite you to read on and discover what these keys are and how to use them.

1. Abloy Key

You’ll use this type of key to unlock any disc tumbler locks. They will rotate the enclosed discs to release the lock when they align correctly. For the most part, this key type isn’t popular or known in the majority of the world. However, they’re extremely popular in other parts. If you were to visit Finland, you’d find this type of lock on almost every door as the standard practice. Since they’re not spring-loaded like a host of other locks, this one is virtually impossible to pick. This makes these locks and key sets a very good choice if you want to upgrade your home’s security system.

2. Cruciform Key

Better known as a cross key, this type of key has a profile that is an X shape to it. You’ll commonly find it used in industrial settings because you need reliable and hard wearing keys to ensure that they last. They’re very efficient and strong, but they also have a very compact design that makes them useful in a large range of applications. When you get this key, you’ll get a key that has four flat sides with teeth in various patterns along each of this key’s edges.

One big advantage to this key is that it has a very unusual shape to it, and this makes picking it very challenging. In turn, it gives you peace of mind that your property and all of your garden tools are protected. One drawback is that it is relatively easy to duplicate these keys, so you really want to ensure that you keep it in a safe space where people can’t take it and copy it.

3. Dimple Key

As the name suggests, it’s easy to identify these keys due to the dimples along the key’s blade. You can get dimples in several sizes, and the dimples correspond with the pins that protrude inside the lock. For this type of key to work, you have to put it in the lock and allow the dimples to line up with the pins. If they do, they’ll release the lock.

The dimple key will be the same on both sides, and this allows you to insert them both ways into the lock and have them work. So, opening your door is much easier because you don’t have to worry about trying to insert the key in the right way, and you get quicker access. You traditionally use these keys to protect your property by keeping intruders out, and they’re popular for home security measures.

4. Double or Four-Sided Key

This is the most common type of key that you use to secure your home or shed. You can identify these keys by looking at the teeth. They’ll come with two or four sets of teeth on different sides of the key’s blade. The better option for increased security is the four-sided key because they’re very challenging to duplicate. In turn, they’re a very unlikely target for thieves. The different teeth lines on this key also means that the lock is much more complex, and this makes it harder to pick.

If you’re on a tighter budget and you want to upgrade your security levels in your home, you can switch your locks and keys over to this type of key. It helps you drastically improve your home’s security without spending a lot of money or taking a lot of time. These keys are also much more sturdy and less prone to snapping should you get them stuck in your lock.

5. Keycard Key

This key looks a great deal like a traditional credit card. They feature the same material, and they’re the same shape and size. This is very convenient because it makes it easy to store any keycard you have in your wallet in your credit card compartments to keep it secure. You’ll find this key used in hotels a lot, and this is most likely where you’ve experienced using them firsthand. They’re also popular in large offices and government buildings where the employees need access but it has to be restricted.

You electronically program these keys to be able to open certain door locks. They’re great in a hotel because it’s quick and easy for the staff to program them to open specific rooms while not allowing access to the others. They also deactivate after the stay, so it’s not a big deal if a customer loses one or forgets to return it when they leave. If you had metal keys in this scenario, you’d spend a lot of money and time replacing the keys and locksets everytime a customer walked away with it or lost it.

Keycards also offer a high level of security since the locks work electronically and make it impossible to pick. Also, each keycard goes to a specific lock, and they won’t open every lock. They work well in large buildings or offices where staff have to have access to some areas and restricted access in others. Instead of giving your staff several keys, you can give them a single keycard that you program to open the exact doors that they have the clearance for. It’s very easy and quick to program them using a computer program, so this makes it cost-effective.

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You can program key cards to work for a set amount of time, and they’ll automatically deactivate once the time is up to secure the room. This is good if someone takes the card with them when they leave on accident. Keycards by Matthew Purdy / CC BY-ND 2.0

6. Laser Cut Car Key

As the name suggests, these keys get cut using a laser. You may also hear them called internal cut keys or sidewinder keys because you get identical cuts on either side of the key. This allows you to insert your key into the lock any way you want and it’ll work, and this makes them popular as car keys. They also have square or blunt edges on the key’s blade that make them easily recognizable.

Due to the precision that goes into making these keys, they’re extremely difficult to create a second copy, and this helps reduce car theft. You’ll need speciality machines to create a replacement or spare key if you were to lose one. Locksmiths need to use an internal machine that they put your blank key in to cut both sides at the same time.

7. Magnetic Key

This type of key has several magnets, and the exact amount will depend on the way they face and their size. The magnets cause the lock tumblers to line up and let go. They use a passive system to operate, and this means that you don’t need any electronics. You can use them in a host of locks, including deadbolts, cylinder locks, and lever locks.

Since the magnet combination needs to be so specific to open your lock, they can offer a good level of security for your home. You can’t pick any lock that uses this type of key because no physical force can make the tumblers move. They’re also very difficult to duplicate, and this adds another layer of security to them.

8. Mechanically Cut Key

A mechanical cut key is a type of key that you find for older shed doors or doors in offices or homes, or used in older car models. They get cut on a single side, and the ridge pattern will correspond with the matching lock. These keys get created using mechanical cutting machines, or you can die-cast them. However, this also makes them one of the easiest keys to duplicate, so it’s one of the least secure and safe. They also have a very basic design to them, and you can make replicas in your local hardware store. If you have a self-service key cutter, you could even duplicate it yourself, and you can find one in several big box stores.

It’s also very inexpensive to copy these types of keys. So, if you have a lock that uses a mechanically cut key, you have to be careful that the wrong person doesn’t get ahold of it. If they do, in a few minutes and for less than $10.00, they could gain access to your home, car, safe, or office. If this concerns you, it’s a good idea that you upgrade any locks that take these keys with something much more secure.

9. Paracentric Key

This is a type of key that is very uncommon to see used in everyday life. It’s more rare because one of the only places you’ll see them commonly used is in prisons. You can identify this key as having a very contorted blade on one side with a blade and a lot of tiny teeth lined right next to it.

The locks that come with this type of key were very difficult to pick, so this made them a great way to discourage lockpicking. The popularity for using these keys in prisons was due to the belief that you couldn’t pick the locks, so they would theoretically keep any prisoner securely locked up. However, this isn’t necessarily true because people have figured out a few ways to pick and access the locks without using a key.

10. Primary Key

Just like the name suggests, a primary key is a type of key that locks and unlocks a building’s main door, and it can open every door in said building. This is why it’s also referred to as a master key. There are other keys that will open specific locks inside the building, but the primary key can unlock every one.

It’s nice to have this type of key in office buildings, and you can easily give each employee a key that corresponds with the lock on their office. The manager will have the primary key because this lets them get into any office in the building if there is an emergency. Since the key can open any door in the building, the person who has it has a great responsibility. You should also keep it in a safe place to keep the building secure.

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A primary key can open multiple doors in a building, and it’s common for managers and security personnel to have them to allow them to quickly get into every room. Key by Mike / CC BY-NC 2.0

11. Smart Car Key

As the name suggests, this type of key works for vehicles. They function just like transponder keys do. They use radio signals and microchips to operate, and they have antennas fitted inside your vehicle’s bodywork. They also don’t require you to manually insert them into the car’s ignition to start it. Instead, all you have to do is push a button in your car to turn the ignition on, and this will only work if the key is in the car, anywhere from your glove box to your pocket. If you don’t have the key, it won’t start.

This key can also unlock, lock, and open your car doors automatically. This allows you to push it as you’re walking toward your car to open the door right when you get to it. They’re very difficult to copy, and this makes them very safe. You’ll have to go to the car manufacturer to get a copy of it if something happens to your original.

12. Skeleton Key

This type of key is also called a passkey, and some people refer to it as a primary key too, but this isn’t correct. The confusion comes in because this key can also open several locks in a home, but you only use this key in conjunction with warded locks. You’ll get a protruding, serrated part on the tip of the key’s shaft, and a lot of the time, it gets sanded down to fit several locks.

For the most part, people don’t use warded locks anymore because they’re relatively easy to pick, so they don’t make a good security measure for anyone wanting to get in. Some older homes might have this type of lock on their doors, but it’s heavily recommended that you add additional locks if this is the case to make it more secure. Locks that use skeleton keys to open only have a spring or lever as the internal active component, and it’s easy to manually pick it.

13. Transponder Key

You’ll commonly find this key type in modern cars or newer vehicles, and many people refer to this type of key as a chip key. The chip portion of the name comes from the fact that there are microchips in the key that correlate to the car ignition’s code. They use a radio signal to work, and it gets triggered when you put the key into the ignition. They’re also extremely safe as they’ll only work with the car and no other ones.

The keys are impossible to duplicate, and this increases the safety factor by reducing the chances that anyone can steal your car unless they have your specific key. If you try to put the wrong key into your car’s ignition, it can cause some cars to shut down completely, and this prevents theft.

Since these keys cost a large amount of money to replace and they’re difficult to replicate, they are widely considered to be one of the safest types of keys available on the current market. A key cutting machine can’t create one of these keys, and a locksmith will have to have access to your particular database from the vehicle manufacturer to get the code that matches your car to make a new key.

14. Tubular Key

A tubular key is also called a barrel key, and you use them to open locks that are the tubular pin design. These locks are on several pieces of equipment, and you’ll find them on everything from bicycle locks to vending machines. They have a very unique look that makes them easily identifiable.

You’ll see a cylindrical shaft that has a hollow design. This is what you put into the lock. They offer a good level of security because they’re hard to duplicate. If anyone who wants to break in notices that it has this type of lock, they’ll be discouraged to break in.

15. Valet Key

Valet keys are types of keys that are specifically designed to help ease your mind when you use valet services. They get programmed to open the car doors and start your ignition. You’ll get special coding in each key that will disable them and stop them from getting used on other parts of the car, including the glove box or trunk.

These keys are excellent for giving to a valet service instead of giving them your actual car keys and giving someone you don’t know access to your car. A lot of people think that these keys are car door keys, but they’re not the same. A car door key gets programmed to let you open your locked door. A valet key lets you open the door and start the ignition.

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Valet keys are very popular in larger cities because they allow valets to only open and start the car, and they can’t get into other key locked areas. Valet Key by ⊙ ☂︎♙₪୬〰⋀ℵ⊃△ ⊙ / CC BY 2.0

16. VAT Keys

VAT stands for vehicle anti-theft, and this type of key can help stop people from stealing your car. It’s possible to upgrade almost any car key to this type for extra security, and they come with a microchip embedded into the key’s body with a code that matches your car. This means that it’s impossible to use the key on another car or to use another key to start your car.

The keys are very expensive if you have to replace them, so you do want to keep a very close eye on them if you choose to upgrade your car with them. If you lose it, it can cost hundreds of dollars to get another one.

Six Common Uses for Keys

Although there are arguably hundreds of uses for different types of keys, we’re going to pick out the top six. This way, you can see how versatile this small tool is, and it may give you a new appreciation for them.


Diary keys and locks are more for show than security, but they’re nice to have if your kid is having a sleepover and wants to keep their private thoughts from prying eyes. They’re light, small, and dainty, and they usually all have the same shape. So, if you lose the keys, you can usually open the lock using a different diary’s key. You could also buy the same diary online and use those keys. They usually come with at least two keys in case you lose one.


Every modern car has a key to operate it. Car keys are one way that you can lock or unlock the doors to keep it safe from any intruders, but they’re also vital to starting the car so you can drive it.


If you live in a house or apartment, chances are, you have a key. You use keys to lock up the properties to keep everything safe and secure against any intruders. You could even have a whole set of keys to work on different locks in the house, including the back door, front door, garage, windows, gate, and you could even have keys for your shed.

Since most people see their home as a safe space where they keep their items, their children sleep, and where they make memories, it’s more than worth it to invest in a high-end type of key and lockset that is difficult to pick.

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There are dozens of types of keys you can use for your house locks, and it’s easy to upgrade them to make them more secure. Keys by Anna L Martin / CC BY 2.0


Any office building that has locks on the doors gets secured with keys. In larger buildings with several offices, you may need several keys to get around the area if you don’t have a master one.


You can use padlocks to secure a huge amount of objects or spaces, and you’ll need a type of key to open them. People who visit the gym regularly may have a padlock to keep their belongings secure in their locker, or you may have a padlock on the gate to your property. There are also tiny padlocks on journals or personal diaries, and bicycle locks typically have this lock.

However, padlocks are fairly easy to open, and you can usually pick them without a lot of trouble. It’s also easy to duplicate the key. If someone really wants to get in, they can use an angle grinder or a bolt cutter to remove the whole lock without using a key.


You can operate your safe with pre-programmed codes or keys. A safe is a rugged box that you use to secure your valuable items or important documents. You’ll usually find them in hotels in the back of wardrobes, in restaurants or bars in the back office, or hidden throughout people’s homes. Banks have more intelligent and complex safe types that can hold everything from jewelry pieces or large amounts of money.

Bottom Line

We’ve outlined 16 different types of keys and their purposes for you, and you can take this information and decide which locks and key sets you want to have in your home, office, or vehicle. Some are easier than others to pick, so keep this fact in mind when you make your final choice.

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