What Do the Numbers on My Key Mean?

Updated on February 10, 2018
Tom Rubenoff profile image

Tom spent 17 years as a commercial locksmith and over 20 years in door hardware distribution.

Source

The Four Categories of Key Numbers

Keys have all kinds of numbers, letters, and symbols on their heads. Some are stamped into the metal, while others are embossed during the molding process. I've provided this guide to describe the information contained in the letters and numbers.

The numbers chiefly fall into the following four categories:

  • Bitting Numbers
  • Key Blank Model Numbers
  • Key Numbers Within a Master Key System
  • Key Code Numbers

FIGURE 1
FIGURE 1 | Source

The Anatomy of a Key

To understand the numbers and letters, you need to know the different parts that make up a key.

  1. Bow/head: The bow works as the handle you use to hold and turn the key. Most key numbers appear here.
  2. Stop: Located next to the bow on most keys, the stop keeps the key from going too far into the lock. Distances are measured starting at the stop to locate the cuts. On certain types of keys, the stop is located at the tip (end) of the key rather than the bow.
  3. Blade: The blade is the business end of the key and is where the cuts that correspond to the key's bitting are located.
  4. Cuts: In order to make a standard pin tumbler key, you need to cut material away to specific depths to accommodate the length. These depths are numbered according to their size in thousandths of an inch. For example, a number one (1) cut may be .213" (two hundred thirteen thousandths of an inch) on a particular key brand. Listed, these depth numbers comprise the bitting of the key. If a key has no cuts, it is not called a key. It is called a "blank."
  5. Tip: You can find the tip at the opposite end of the key from the bow. It's used to identify the order of a bitting. For example, you could say the bitting on this key is written "bow to tip".

The illustration above shows the different components of a key.

FIGURE 2
FIGURE 2 | Source

What Are Bitting Numbers?

In the photo, Figure 3, above, we see a close up of the head with a five-digit number towards the bottom. This number is the bitting. If we look at these digits one at a time and then look at the blade of the key in the photo, Figure 4, below, we see that the first cut (starting from the bow end) is a number "2" and not so deep. The second cut, a number "6," is significantly deeper. If we compare the cuts to their corresponding numbers in the bitting, we can see that the larger the number, the deeper the cut. This is typically the way bittings are constructed. By comparing the numbers to the cuts, we can tell that the number stamped in this key is, in fact, the bitting.

FIGURE 3 - The cuts
FIGURE 3 - The cuts | Source
FIGURE 4 - The Keyway of a Key
FIGURE 4 - The Keyway of a Key | Source

The Keyway of a Key

In this case, the stop shows the letter "C". On many Schlage keys, this is where the keyway of the key is shown. The keyway is the shape of the key when viewed from the tip and determines whether or not the key will be able to enter the keyhole of the lock. You can see this in Figure 3 (above).

Bitting numbers can come in a number of formats. Yale Locks, for instance, places an "A" before their bitting numbers to differentiate them from key code numbers. A 6-pin bitting number stamped into the bow of a Yale original key would look like this: A298837.

Figure 3a - Is This Key an Imitation or an Original?
Figure 3a - Is This Key an Imitation or an Original? | Source

How to Know If a Key is an Imitation

In Figure 3a (above), we have what appears to be another Schlage C keyway key with a bitting number on it. Because it does not show a manufacturer's name, however, we can't assume it is a Schlage original. We can see by close examination that the numbers seem to match the depths of the cuts, but we would need to measure them to see if the cut depths are the same as those on a manufacturer's original.

You can use a micrometer to compare cuts on an imitation key with cuts on an original key. If you find a discrepancy of more than two or three-thousandths of an inch (.003 inches), then it is likely the key is an imitation. If it is an imitation, the bitting is useful only to the factory that made the key in the first place.

Using Bitting Information

In Figure 4, we flipped the key over and the manufacturer's name is prominently displayed. We know the name on the key is the manufacturer of both the key and the lock.

The information we have so far is:

  1. Original manufacturer
  2. Keyway
  3. Bitting number

With these three pieces of information, a locksmith can cut a key for you. If you request a Schlage key with a "C" keyway and bitting number of 26495, the locksmith can make this for you. They can even key another lock to work with the same key. Even more amazingly, the locksmith can do both things without ever having seen or touched the original key. Magical, isn't it?

On the other hand, if the locksmith didn't know the original manufacturer, as with the key in Figure 3a, it's quite likely that the keys made or locks keyed using that bitting would not work properly.

Figure 5:  A Key Blank
Figure 5: A Key Blank | Source

Key Blank Model Numbers

Key blank model numbers appear on the bows of aftermarket blanks. They're used by key duplicators to make copies of keys. When you go to a hardware store or to a locksmith to get a key cut, they copy your key onto a key blank by making cuts in the blank that match the cuts on your key. They can't use any key blank because it must have the same keyway and length.

For keys that fit pin tumbler locks, the key length is described in terms of the number of pin tumblers in the lock that they are designed to operate. For example, Schlage C keyway key blanks are available in 5- and 6-pin lengths.

The blank in Figure 5 (above) was made by the Ilco company, a major manufacturer of key blanks. Notice it has two model numbers. The first number, L1054B, is Ilco's traditional key blank number for this particular blank. The second number, IN8, is probably an Ilco "EZ" number - a system of numbers used primarily for more common key blanks.

Numbers used by key blank manufacturers should not be confused with part numbers used by original manufacturers. The manufacturer's part numbers are usually quite different. For example, the Ilco number for the 5-pin Schlage C keyway blank is 1145, whereas Schlage's part number is 35-100C. ESP, another key blank manufacturer, would call it an SC1 key blank, and this is the Ilco EZ number as well. This shows us that several numbers can be used to identify any given key blank.

Nevertheless, if you can determine the manufacturer of the key blank and the part number used by that manufacturer, you should have enough information for a locksmith to identify the blank you need to cut the key or change the lock. From that information, the locksmith can tell what keyway you have and how many pins are in your lock.

Figure 7 - A Key in a Master Key System
Figure 7 - A Key in a Master Key System | Source

Key Numbers in a Master Key System

Traditional key numbering within a master key system goes like this:

  • The Master Key is key number "A"
  • Sub-master keys are numbered "AA", "AB", "AC," etc.
  • Operating (or pass) keys under each sub-master will be numbered "1AA", "2AA" etc. under the AA sub-master, "1AB", "2AB" and so on under the AB master.

So, when you see a key with a number ending with a letter or two, this probably means it is a passkey in a master key system (see Figure 7 above).

In a master key system, key bittings are designed so every key only opens the door or doors it is intended to open. Therefore, every key is planned and recorded. If the master key system is administered well and you can find who administrates it, you can find out what lock or locks a key operates.

What do you think "1C" means, there on the head? I bet it's the keyway.

Figure 8 - A Key With Code Numbers
Figure 8 - A Key With Code Numbers | Source

Code Numbers

Code numbers are generally found on keys for cabinets, alarm boxes, office and industrial equipment, bike locks, padlocks, and other locks not found on pedestrian doors. Like a master key system, keys with code numbers are recorded and administered. Theoretically, if you lost the key but kept the number, you would be able to get a new key cut.

However, there are published and non-published key codes. Some code numbers are published in books for locksmith use. Some aren't published in those books, so you can't get them from a locksmith. Keys with unpublished codes can only be obtained from the manufacturer with written authorization from the owner of the key, as noted in the manufacturer's records.

Notice the key in Figure 8 (above) has a code with a letter and a few numbers. The format is similar to that of a key in a master key system, and you could think that it is such a key if you didn't know better. The size and key configuration indicate to the locksmith that this is a key by code and not in a master key system. In this example, the size and cut prove this key is not a key in a master key system. Therefore, the number is a code number.

Beyond Key Numbers

You can often find other letters and symbols stamped on key bows. Most locksmith shops, maintenance stores, and real estate offices are equipped with a set of 1/8" letter and number stamps. Many times, people will stamp "MASTER" on the head of the master key for a building for easy reference and fail to consider the security problems that can result. You can also see the ubiquitous "DO NOT DUPLICATE" message coupled with the name and number of your local trusted locksmith.

A bitting conveys the distances measured in thousandths of an inch. Key codes and key number in a master key system point to a bitting number recorded within an organization. Key blank numbers reveal shapes. Key numbers help us visualize the simple and complex functions of the commonplace key.

Figure 6 - An Arrow Lock Company Original Key Blank
Figure 6 - An Arrow Lock Company Original Key Blank
Figure 6a - An Arrow Lock Company Original Key Blank
Figure 6a - An Arrow Lock Company Original Key Blank

A Question to Unlock

Figures 6 and 6a (above) show an Arrow Lock Company original key blank. Can you guess the keyway from the bow markings?

Questions & Answers

  • I found a key with "ALPHA" on the front and "8000" on the back. Where is it from? There is a bow and Leaves at the front, and leaves at the back.

    There is a manufacturer of steering wheel locks for cars called Alpha. Perhaps this is a key for one of their products.

  • I found a key in my deceased dad's clothes. It's a Baldwin gold-color key with numbers on it: 53479. Do you have any clue what the key is for?

    Baldwin is a manufacturer of high-end locks used mostly in residences. These locks are typically installed on exterior or entrance doors. Baldwin stamps the bitting on the heads of their keys, so 53479 is the combination of the key.

  • I found a key. On one side at the top is the letter F, and on the other side is the number 13623. What kind of key is this?

    "13623" sounds like a five-pin bitting, and "F" sounds like a keyway. If I had to guess I would guess this is a key to a light commercial doorknob, lever lock or deadbolt, or perhaps a mortise or rim cylinder.

  • My key has the number L5817 on it. What is this key for?

    The presence of the letter "L" would hint that L5817 is a blind code, but without further information, that's all I can tell you.

© 2013 Tom Rubenoff

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    • Tom Rubenoff profile imageAUTHOR

      Tom Rubenoff 

      3 months ago from United States

      Hi there. 1054LB and IN8 mean the same thing. They identify the key blank. These numbers do not identify this particular key. This kind of key is usually used in cabinet locks.

    • Tom Rubenoff profile imageAUTHOR

      Tom Rubenoff 

      4 months ago from United States

      Interesting that your original keys say Y11 - I have not run into that before. Most companies use key blanks coined with their company name so as to advance their company.

      The industry standard for non-interchangeable core key bittings is bow (that is, head) to tip.

      I think your guess at the bitting you have is a good one. There may be some trial and error involved as you try to find more locks keyed alike the locks you already have. An additional step you could take would be to use a micrometer to measure the depths. Then you can see if a "3" on one key is the same as a "3" on the other key. This might help you determine if you are on the right track.

    • profile image

      Clhug 

      4 months ago

      Thanks for the info! These are the original keys that came with the locks, not copies. They're even all still on the little spring ring that they come on in the package. (I have 6 keys, 2 each on 3 spring rings, because I bought 3 locks originally.)

      The key number listed on the package of the new lock I just bought that ALMOST matches visually is 33443, but I don't know if that's the bitting or the blind key code, and it has one little extra notch closest to the head of the key that the old key doesn't have.

      If that number is the true bitting, is bitting listed from the tip of the key, or the head of the key? Or can it be different for different manufacturers?

      Actually, I look at the key cut and number on the new key, I think it might be true bitting, listed from the tip. Visually looking at the key, starting at the tip, I see 2 cuts of the same depth (the 33), followed by 2 cuts deeper than the first 2 but also the same as each other (44), followed by a 5th cut that appears the same depth as the first two cuts (the final 3).

      So I THINK that tells me I'm probably looking for a 33440 key cut to match my old keys.

      Would that make sense? (Of course I still don't know for sure whether the number is the true bitting, or a blind number, but IF it's the bitting, then am I reasoning through it correctly?)

      Thanks again!

    • Tom Rubenoff profile imageAUTHOR

      Tom Rubenoff 

      4 months ago from United States

      Y11 is a key blank number used by aftermarket key blank companies, so if your keys all say Y11 on them, they are probably all copies, and none of them will have the cam lock manufacturer's name on them or the key code. Many cam lock manufacturers use this keyway, and since key codes are categorized by manufacturer as well as lock type, it may be difficult to find the one you are looking for.

      The key number (or key code number) might be published in a key code book. Next to the key number in the book would be another number: the bitting of the key, which is a set of numbers that correspond with the depths of the cuts on the key. Usually "1" stands for the shallowest cut and "9" or "0" for the deepest, but cam lock keys don't usually have that many choices. Usually their cut depths are limited to 1 through 4 or 5, and they usually only have 4 cuts, which means there are a few thousand possible bittings that could exist. However, most manufacturers only use a few hundred bittings at most for their cam locks.

      To find your key's code in a code book, you would first identify the bitting. Having no guide, you would need to guess. Very shallow cuts are probably a "1", very deep cuts a "4" or "5", and in-between depths probably a "2, "3" or "4". If there is no cut at all, that would be a "0". After you guess at the bitting, say it's "1422", you start looking for "1422" in the code books. If you're lucky, maybe you'll find someone who has code books on searchable .pdf documents. That would speed things up.

      Another possibility is to have a locksmith key cam locks to your key. I have done it, so I know it is possible to do. It is no fun, but it is possible. Most cam locks can be disassembled, and their pins or wafers replaced to match a key. In this case your project would be to find a locksmith willing to do this work.

    • profile image

      Clhug 

      4 months ago

      For a Y11 key for a camlock, can the key number be determined based on the cut of the key?

      I have several cabinets that I installed camlocks in several years ago and made sure to buy locks with all the same key. I now need to install a new camlock in a new cabinet and I want to match the key. Unfortunately, the keys that came with the original locks do not have the key number stamped in them (they have "Y11" stamped on them, but not the specific key number), and I don't have the original packaging of the original locks (it was 5+ years ago at least).

      To be clear, I am NOT looking to make a new key for my existing locks. I am trying to buy a new lock to match my existing key.

      I tried taking my existing key to the hardware store and just going through their stock of locks and visually comparing the cut of the key. I found one that looked right and bought it, but once I got the new keys out of the package, there was one TINY little difference which is enough to make the keys not be interchangeable.

      Thank you!

    • Tom Rubenoff profile imageAUTHOR

      Tom Rubenoff 

      5 months ago from United States

      Seek a locksmith who has code books. If the number is a published key code, they may be able to discover the manufacturer.

    • profile image

      nobody 

      5 months ago

      i found a key and it has this written on it, ODC 117. do you know what that means. do you happen to have any information that might help me find out what it fits into or maybe a website i look it up on?

    • Tom Rubenoff profile imageAUTHOR

      Tom Rubenoff 

      7 months ago from United States

      Hi Hardik, according to Kaba Ilco's online key blank cross reference, 1444 could mean it is a key for an Alfa Romeo motor vehicle. On the other hand, it could be a bitting number or a number assigned to an operating key in a larger key system, or a code that a locksmith might be able to look up in order to make a new key should this key be lost.

    • Tom Rubenoff profile imageAUTHOR

      Tom Rubenoff 

      7 months ago from United States

      Hi Gemma, unfortunately the number on the key is probably not a clue to who might own the key. The manufacturer's name, if there is one, may help you determine what kind of lock it may fit, and that may or may not be a clue. Did the key arrive by mail? If so, is there a postmark showing where it was mailed from? That would be a better clue.

    • profile image

      Hardik thakor 

      7 months ago

      Hi what the meaning of key number 1444

    • profile image

      Gemma 

      7 months ago

      I got a key in my letterbox with a card saying save the bees there is a number on the key how do i find out who it belongs to

    • Tom Rubenoff profile imageAUTHOR

      Tom Rubenoff 

      7 months ago from United States

      Hi Cindy,

      "Independent Lock Company" later shortened their name to "Ilco." Since then they were bought by Kaba, which has in turn been recently acquired by Dorma. They remain a maker of key blanks, key machines, locks and cylinders, as they have been for many decades.

      Without any other clues, I think your chances of finding the lock this key fits are slim to none. It sounds like your key probably fits a replacement cylinder that was used to change a lock somewhere. You could look for a cylinder face with the same logo in the building in which you found the key, but since Ilco has long made cylinders with no logo on the face, even this small possible clue may not apply.

    • profile image

      Cindy 

      7 months ago

      I just found an old key with the writing independent lock company on it. Also ilco and made in the USA is there any where I could find out where this might go to

    • profile image

      Ingrid 

      10 months ago

      What do the numbers on a USPS key mean? My mother just passed away and she has 3 on her key ring, but I do not know where the boxes are? How do I locate them?

      #s are 00128 74796 and 69331

      Thank you

    • profile image

      Antoinette Spencer 

      12 months ago

      I have a small key silver it has the numbers 555 on it I'm really curious about what this key means and what it belongs to

    • profile image

      Curtis 

      12 months ago

      I work for a Assisted living facility, I have keys marked 1AA through 101AA. I have duplicate keys that someone cut. I'm missing some keys and instead if trying all the keys I was wondering if there is a list of the cuts so I can check the number against the cylinder. IE. I have cylinder 46AA with no key.

    • Tom Rubenoff profile imageAUTHOR

      Tom Rubenoff 

      4 years ago from United States

      I will actually write a separate article on that subject, but in short, numbers on locks and keys might be code numbers that may enable a person to cut a key based on that number if (1) the key code is a published code, that is, available in commercially available key code books, or the manufacture keeps the code on file and will translate the code; and (2) the person doing the key cutting is equipped for and skilled in cutting keys by code.

    • profile image

      David Mathibe 

      4 years ago

      Can you explain the numbers and letters on a padlock can determine a working key if lost your keys.

    • Tom Rubenoff profile imageAUTHOR

      Tom Rubenoff 

      4 years ago from United States

      I am glad you enjoyed!

    • profile image

      rcorcutt 

      4 years ago

      This article was awesome. I use a lot of keys at my work and I have always had this almost nerdy curiosity about what the numbers mean but I never looked it up. Thanks.

    • Tom Rubenoff profile imageAUTHOR

      Tom Rubenoff 

      5 years ago from United States

      Thanks, FlourishAnyway. I have found the interaction between keys and locks interesting for a long time. The numbers and letters stamped on keys and the meanings of those characters is as complex as the evolution of the key. Thanks again.

    • FlourishAnyway profile image

      FlourishAnyway 

      5 years ago from USA

      I've noticed the numbers before but never thought a whole lot about it. Who knew? Thanks for tell us this information. I find it intriguing.

    • epbooks profile image

      Elizabeth Parker 

      5 years ago from Las Vegas, NV

      My pleasure!

    • Tom Rubenoff profile imageAUTHOR

      Tom Rubenoff 

      5 years ago from United States

      There is no higher praise than to learn that one's writing has been of use. Thank you, Epbooks!

      Livewirez, all keys are unique, and so every duplicate is just a little off. The difference of the copy from the original is what determines how well (or badly) it operates the lock. People who duplicate keys generally use a key machine that "reads" the information from the key and simultaneously transfers that information to a cutting wheel that makes the cuts. But it is also possible to duplicate a key using a simple flat file.

      Hmm. I feel another hub coming on. Thank you!

    • livewirez profile image

      Romel Tarroza 

      5 years ago from Pearl of the Orient Sea

      Nice Hub.. I know that keys are very unique but I am just curious how does those people who duplicate keys can make keys exactly the same as the original?

    • epbooks profile image

      Elizabeth Parker 

      5 years ago from Las Vegas, NV

      One thing I can honestly say that I never looked at other than its color was a key. I use them every day, but never even noticed there were numbers on them. This is good to know in case I need to get some keys made, which, as a matter of fact, I do!

    • Tom Rubenoff profile imageAUTHOR

      Tom Rubenoff 

      5 years ago from United States

      Thank you, Storyteller. It does seem that there is often a key to something that figures prominently in mysteries and detective stories; and there are all the key metaphors, too. Thank you!

    • Storytellersrus profile image

      Barbara 

      5 years ago from Stepping past clutter

      Fascinating information- great material for a book or poem of intrigue!!!

    • Tom Rubenoff profile imageAUTHOR

      Tom Rubenoff 

      5 years ago from United States

      Glad you liked it and thanks for reading! It is the kind of information that is occasionally very nice to have. Thanks again.

    • tastiger04 profile image

      tastiger04 

      5 years ago

      Interesting! I've always noticed the numbers on my keys, but never knew what the deal was....thanks for the good read! Voted up and interesting :)

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