Microchipping Your Cat and Keeping Pet Documents in Order
How cat microchips work, why registration matters, collars and ID tags, and which records and documents every cat owner should keep.
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Every year, huge numbers of lost cats end up in shelters without identification. A microchip is the most reliable way to make sure a lost cat can be returned to you — but only if the chip is registered with your current contact details.
How microchips work
A microchip is a tiny transponder about the size of a grain of rice, implanted under the skin between the shoulder blades with a needle. It has no battery and no GPS. When a vet, shelter or animal warden passes a scanner over it, the scanner reads a unique number. That number is looked up in a database to find the owner.
- It takes a few seconds and is similar to a vaccination; no anesthetic is needed, though it's often done during spay/neuter surgery.
- It lasts for life.
- It's legally required for cats in some countries (for example, in England for most cats over 20 weeks of age since 2024) and for international travel. Check the rules where you live.
Registration: the step people forget
A microchip is useless if the database has no details — or old ones.
- Register the chip in your name as soon as you get your cat. If you adopted or bought the cat, the previous owner or shelter may need to transfer it to you.
- Update your details whenever you move or change your phone number.
- Note the chip number and the database it's registered with, and keep it with your cat's documents.
- Ask your vet to scan the chip at annual check-ups to make sure it can still be read.
Collars and ID tags
Collars can help people recognize that a cat has a home, and a tag with your phone number allows a neighbor to call you without visiting a vet. If you use a collar:
- Choose a quick-release (breakaway) collar that opens under pressure, to prevent strangling if it catches.
- Fit it so two fingers slide underneath.
- Check regularly for rubbing, especially in kittens as they grow.
- Some owners use microchip-activated cat flaps and feeders, which read the chip and let only your cat in.
GPS trackers are available for cats who go outdoors, but they need charging and a collar.
Documents to keep
Keep a folder — paper or digital — with:
- Adoption or purchase contract, plus pedigree registration papers if applicable
- Microchip number and database details
- Vaccination record or pet passport, including batch numbers and dates
- Medical history: spay/neuter certificate, test results (FeLV/FIV), allergies, ongoing medications
- Pet insurance policy details and claim contacts — see pet insurance
- Your vet's contact details and the nearest 24-hour emergency clinic
- Recent clear photos of your cat from several angles (crucial if they get lost)
- Written landlord permission if you rent — see cats in rented homes
If your cat goes missing
- Search your home thoroughly first — cats hide in astonishing places — then search nearby gardens, sheds and garages, especially at dawn and dusk when it's quiet.
- Report your cat as missing to the microchip database, local vets, shelters and animal control.
- Post in local lost-pet and neighborhood groups with a photo.
- Put up posters and ask neighbors to check sheds and garages.
- Place your cat's used litter or bedding outside your door; familiar smells can help guide them home.
For travel abroad, see taking a cat abroad.