Pet microchip numbers can provide useful clues about a chip, including the system under which it was issued. However, the number does not tell us everything about the animal, its owner or its current registration.
Most modern pet microchips have 15 digits, but older 9-digit and 10-digit chips are still in use.
This guide explains what the digits can tell us, what they cannot prove and why the complete number matters.
What does a pet microchip number look like?
A pet microchip number is the unique identification number stored on the chip implanted in the animal.
It may contain:
- 9 digits
- 10 digits
- 15 digits
Most modern chips use the 15-digit international format. Shorter numbers are usually connected to older identification systems.
The chip itself normally stores only the identification number. The owner’s name, telephone number and other contact details are held separately by a microchip registry.
The AAHA Microchip Registry Lookup tool accepts valid 9-digit, 10-digit and 15-digit chip numbers.
Why do most modern microchips have 15 digits?
The 15-digit format follows international standards for electronic animal identification.
A number may look like this:
900111000123456
The complete number identifies one chip. Different parts of the number can also provide clues about the system, country or manufacturer under which it was issued.
The first three digits are usually the main prefix. They may be a manufacturer code or an authorised numeric country code.
The following digits complete the chip’s unique number. In some systems, they can also show a product range or another type of allocation. For certain ranges, an additional digit can help distinguish a normal chip number from a test or reserved number.
This is why ChipTrace checks the complete number rather than looking only at the first three digits.
What do the first three digits mean?
The first three digits are often the best place to start when investigating a 15-digit chip.
They normally represent one of two things:
- An authorised numeric country code
- A manufacturer code
Manufacturer codes are commonly found between 900 and 998. They identify the manufacturer code under which the chip was produced.
A country-coded chip uses the three-digit numeric code assigned to that country under the ISO 3166 system. A country code may only be used for animal identification when the responsible national authority controls and authorises its use.
What is a country-coded microchip?
A country-coded microchip begins with an authorised three-digit numeric country code.
For example, the ISO numeric code for the United States is 840. The United Kingdom uses 826.
The UK code covers the United Kingdom as a whole: England, Scotland, Wales and Northern Ireland. These countries do not each have a separate ISO numeric country code.
Nearby Crown Dependencies are different. Jersey, Guernsey and the Isle of Man however, each have their own numeric codes.
A country prefix must therefore be interpreted carefully. It can point towards a national identification system, but it does not always reveal the exact part of that country in which the chip was implanted.
It also does not prove:
- Where the animal was born
- Where the animal currently lives
- Where the chip is now registered
- That the animal has never moved abroad
A pet may have been chipped in one country and later moved, imported or adopted in another.
A country code is a useful starting point, not a complete history of the animal.
What is a manufacturer-coded microchip?
A manufacturer-coded chip begins with a code assigned to a microchip manufacturer.
These codes are commonly found between 900 and 998.
A manufacturer may supply chips to clinics, distributors, shelters and rescue organisations in several countries. The prefix can therefore identify the manufacturer without showing where the chip was implanted or registered.
When no registration is found, the manufacturer may still be able to help trace:
- The distributor that received the chip
- The country or region that received the batch
- The clinic, shelter or rescue that purchased it
- The registry normally used with that range
Does one prefix always identify one manufacturer?
Not necessarily.
Codes and number ranges can change over time. A manufacturer may use several ranges, while older allocations may later be connected to another company or distributor.
There may also be more information in the digits following the main three-digit prefix.
This is why a prefix should not be interpreted from memory alone. The complete number should be checked against current manufacturer and registry information.
Can a microchip number reveal the pet’s nationality?
No. A microchip number identifies the chip, not the animal’s nationality.
A country-coded number may suggest the system under which the chip was issued. However, the animal may later have:
- Moved abroad with its owner
- Been adopted internationally
- Entered another country through a rescue
- Been registered again after moving
The number can guide a search, but it should not be treated as proof of the animal’s birthplace, nationality or ownership.
What do the remaining digits mean?
The digits after the main prefix complete the chip’s unique identification number.
Depending on the system, some of these digits may also identify a product range, allocation or type of number.
For example, a particular digit may sometimes help distinguish a live chip range from a test or reserved range. This is not a universal rule for every chip, so it must be checked against the system used for that number.
Owners and finders do not normally need to decode each digit themselves. The most important step is to copy and search the complete number correctly.
Why does one incorrect digit matter?
Every digit matters.
Changing, missing or reversing a single digit creates a different number. This may produce:
- No search result
- The wrong manufacturer information
- The wrong country clue
- A completely unrelated registry record
Before searching:
- Compare the number with the scanner display
- Check handwritten numbers carefully
- Watch for similar-looking digits, such as 0 and 8
- Do not guess a missing digit
- Ask for another scan when the number is unclear
Spaces and dashes are not normally part of the chip number.
What is a 9-digit microchip number?
A 9-digit number is usually connected to an older microchip system.
The chip may still work correctly, even though it does not follow the modern 15-digit format.
An older chip can sometimes be harder to trace because:
- Some lookup services do not recognise the format
- The original registry may have closed or changed
- The manufacturer may now trade under another name
- Not every scanner can read every older chip type
A shorter number does not mean the chip is false or broken.
What is a 10-digit microchip number?
A 10-digit number is also usually an older format.
Like a 9-digit chip, it may still identify the animal correctly when it can be scanned and traced.
Do not add zeros to make the number 15 digits. Search it exactly as it appears on the scanner or official paperwork.
Can letters appear in a pet microchip number?
Modern ISO pet microchip numbers normally contain digits only.
Older systems or documents may show letters, labels or other reference numbers near the chip number.
When you are unsure, ask a vet or shelter to confirm which characters belong to the implanted chip number.
Do not include unrelated information such as:
- Spaces or dashes
- Registry reference numbers
- Pet passport page numbers
- Barcode references that are not the chip number
Where can I find my pet’s microchip number?
The number may appear in:
- The pet passport
- The vaccination record
- Veterinary records
- Adoption papers
- A registration certificate
- An email from the microchip registry
When you cannot find the paperwork, ask a vet, shelter or rescue organisation to scan the animal.
Can I identify the registry from the number alone?
Sometimes, but not always.
The prefix may point towards a country or manufacturer, but several registries can operate in the same country.
The animal may also be registered in a different country from the one in which the chip was issued.
A lookup service may identify:
- A registry that holds the record
- A likely manufacturer
- A distributor
- A country or region
- Other databases that should be checked
Can two pets have the same microchip number?
They should not.
A properly issued microchip number is intended to be unique.
When the same number appears for two animals, possible causes include:
- A typing error
- A scanning or copying mistake
- Incorrect paperwork
- A duplicate or wrongly issued number
- A registry data problem
Ask a vet to scan both animals again and contact the relevant registry or manufacturer.
How ChipTrace interprets a microchip number
ChipTrace uses the complete number to guide the search.
Depending on the number, it may:
- Identify a likely country or identification system
- Identify a manufacturer or supplier
- Recognise important information elsewhere in the number
- Select the most relevant registries to check first
- Search connected lookup services
- Show databases that could not be checked automatically
- Suggest the next organisation to contact
ChipTrace treats information found in the number as evidence, not proof.
The number, registry results and manufacturer information must be considered together.
Check a microchip with ChipTrace
Enter the complete microchip number exactly as it appears on the scanner or official paperwork.
ChipTrace will search more than 100 connected registries and lookup services. When no registration is found, it may still provide useful information about the manufacturer, number range or likely country.