Microchipping your cat

A microchip is a tiny implant, about the size of a grain of rice, that carries a number a scanner can read. It gives your cat a permanent identity if a collar is lost. The chip only helps if your contact details are registered against its number and kept current. Whether chipping is legally required depends on where you live.

What a microchip is

A microchip is a small capsule of glass or biocompatible material. It has no battery and no GPS. It does not track your cat. When a vet or shelter passes a scanner over the cat, the scanner powers the chip for a moment and reads its number. That number is looked up in a database, which holds your name and phone number.

The chip sits under the skin, usually between the shoulder blades. A vet or trained person puts it in with a needle, much like a vaccination. Most cats flinch at most. It is not a surgical procedure, and the cat needs no anesthesia for it. Many owners choose to have it done during a neutering operation, because the cat is already asleep. That is a convenience, and you can chip a cat at any time.

Most modern chips follow an international standard and can be read by universal scanners. Older chips of other types exist in some places. A vet can tell you what scanner is used locally.

What to do, step by step

1. Decide when. Many kittens are chipped at the time of their first vaccines or at the time of spay or neuter surgery. Ask your vet what they suggest. A breeder or shelter may already have done it.
2. Ask who registers it. Some clinics register the chip for you. Others give you a form, a code or a website. Find out what step you must complete yourself.
3. Register your details. Give your name, a main phone number, a second contact number and an address. A second contact is useful if you cannot be reached.
4. Keep the record. Store the chip number and the name of the database where you will find them again. Take a photo of the certificate.
5. Update it when anything changes. Move house, change phone number, rehome the cat or lose a family member who was listed, and update the record the same day.
6. Have it scanned. Ask the vet to scan the chip at each annual visit to check that it reads and that the number matches your records. Chips rarely fail or move, and a check costs almost nothing.
7. Keep a collar and tag as well. A breakaway collar with a tag lets a neighbour see you can be reached without waiting for a scan. Both together work better than either alone.

Rules by place

Rules differ widely. In England, owners of cats over 20 weeks old have had to chip them and keep a database record since June 2024, and a fine can follow if they do not. Other parts of the United Kingdom and many other countries have different rules, and some do not require chipping at all. Some countries need a chip for pets entering the country. Shelters and rescues often chip cats before adoption whether or not the law demands it. Check what applies where you live and where you travel.

Registration systems also differ. In some countries there is a single national database. In others there are several competing databases. A cat's chip number may exist on one that you have never heard of. Ask your vet which one holds your cat's record, and keep the paperwork when you adopt.

Microchip cat flaps

A microchip cat flap reads the chip and opens only for cats whose numbers it has stored. It keeps neighbouring cats and other animals out. Read the instructions on how to add your cat's number. A flap does not replace registration.

Common mistakes

• Chipping and never registering. An unregistered chip gives a finder no way to reach you. This is the most common problem.
• Not updating after a move or a phone change. An old number leaves a finder stuck.
• Buying a cat with a chip registered to someone else. Ask for the transfer paperwork, and change the record into your name at once.
• Believing a chip tracks your cat. It does not. It only works if a person scans the cat.
• Assuming a chip proves ownership in every dispute. It is strong evidence. Keep adoption papers and vet records as well.
• Skipping the collar because there is a chip. A tag is the quickest way for a finder to call you.

When to see a vet about a chip

A chip usually causes no trouble. Phone your vet if:

• the skin over the site becomes red, swollen, hot or oozing
• the cat licks or scratches at the area constantly
• the cat seems in pain when touched there
• a scan fails to read the chip

Some cats develop a small lump or a bit of hair loss at the site. Ask your vet to look. If your cat is lethargic, stops eating for a day or more, or has trouble breathing after any procedure, contact a vet at once.

If a chip does not read, a vet may suggest a different scanner or a check on whether the chip has moved. They decide whether a new one is needed.

If your cat goes missing

Call the database first and make sure your details are correct. Then tell local vets, shelters and the council, and give them the chip number. The guide on what to do when your cat goes missing covers the search in more detail.

Summary

• A microchip is a number under the skin, read by a scanner. It is not a tracker.
• A vet or trained person implants it in seconds, with no anesthesia required.
• Registration is what makes it work, and the record must stay current.
• Have the chip scanned at routine visits.
• Add a breakaway collar and tag for fast contact.
• Chipping rules depend on place. Check local law and any travel rules.
• Call a vet if the site looks inflamed or the cat seems unwell.