Microchipping is the modern way to identify pets. Today, microchips are implanted not only in dogs and cats but also in rabbits, birds, horses and even fish. Here’s what you need to know about microchipping your cat, how it works and why it matters.
Microchipping means implanting a tiny chip under your cat’s skin. The microchip carries a unique identification number, usually 15 digits long, that belongs to your cat alone. Most modern chips follow the international ISO 11784/11785 standard. In a typical ISO number:
- the first three digits are often a country code (for example, 840 for the United States and 826 for the United Kingdom) or a manufacturer code (numbers starting with 9);
- the remaining digits are the unique number assigned to your cat.
The chip itself doesn’t contain your name or address. Instead, its number is linked to your contact details in a pet microchip database. That’s why registering the chip, and keeping your details up to date, is so important.
What Is a Microchip?
A microchip is a tiny capsule containing a passive electronic chip and an antenna. It’s about the size of a grain of rice. The capsule is made of sterile, biocompatible glass, which is safe for your cat, protects the chip and is often coated to help it stay in place. Chips don’t have a battery, don’t track your cat’s location (they’re not GPS trackers) and should last your cat’s lifetime.
Read also: Vaccination records and pet travel documents for cats
How Is a Microchip Implanted?
The chip comes preloaded in a sterile, single-use applicator with a needle, similar to a syringe. The kit usually includes barcode stickers with the chip number for your cat’s records.
In cats, the chip is injected under the skin between the shoulder blades. Many cats are microchipped as kittens, often at the same time as their vaccinations or spay/neuter surgery, but cats can be chipped at any age. The procedure doesn’t need anesthesia: it takes a few seconds and feels much like a routine vaccination, although the needle is slightly larger. Some owners choose to have it done while their cat is under anesthesia for neutering.
Microchipping is a quick injection under the skin, and most cats barely notice it.
After the chip is implanted, the vet or technician scans it to check that it works, and the chip number is added to your cat’s records. Then you need to register the chip with a microchip database, and keep your contact details up to date whenever you move or change your phone number.
How Is a Microchip Read?
Vets, animal shelters, rescue organizations and animal control officers have handheld scanners. When the scanner is passed over the cat’s shoulders, it sends out a low-energy radio signal that powers the chip, which then sends back its number. The scanner displays the number, and the finder can look it up in the database to contact you. The chip doesn’t emit any radiation of its own: it only responds to the scanner’s signal. It poses no health risk to you or your cat.
It’s a good idea to ask your vet to scan your cat’s chip at each annual checkup, to make sure it’s still working and in place. Occasionally, chips move a little under the skin or stop working.
Is Microchipping Required?
- England: since June 10, 2024, it has been a legal requirement for all pet cats to be microchipped by 20 weeks of age, and for their details to be registered and kept up to date on a government-approved database. Owners who don’t comply can be fined up to £500. Microchipping is also required in Wales and Scotland for dogs, and rules for cats are being considered or introduced elsewhere in the UK.
- United States: there’s no national requirement for cats, but some cities and counties require pets to be microchipped, and most shelters and rescues microchip every cat before adoption.
- Travel: most countries, including the EU, require cats to have an ISO-compatible microchip, implanted before their rabies vaccination, in order to enter. This applies to cats traveling from the UK to the EU with an animal health certificate as well.
The Benefits of Microchipping Your Cat
- It greatly increases the chances of getting your cat back if it gets lost or stolen. Studies have shown that microchipped cats are many times more likely to be reunited with their owners than cats without a chip.
- Unlike a collar or ID tag, a chip can’t fall off or be removed.
- It’s proof of ownership, which can be important in a dispute, or if you own a rare and valuable cat.
- It’s required for international travel.
- It makes it easier for vets, shelters and other organizations to keep records and identify animals.
- Microchip cat flaps and feeders can use your cat’s chip to let only your cat in, or to give it access to its own food.
Things to Keep in Mind
- A microchip only works if it’s registered and your contact details are current. An unregistered chip, or one with an old phone number, won’t help bring your cat home.
- In the US, there are several different microchip registries. If you’re not sure where your cat’s chip is registered, use the AAHA Universal Pet Microchip Lookup tool online. In the UK, use a government-approved database, such as Petlog, Animal Tracker or Identibase.
- Some older US chips use different frequencies (125 kHz or 128 kHz) than the international standard (134.2 kHz). Most shelters now use universal scanners that can read all types, but if you plan to travel abroad, check that your cat’s chip is ISO-compatible.
- Rarely, there may be mild swelling at the injection site for a day or two.
- A microchip isn’t a GPS tracker. If you want to track your cat’s location, you’ll need a separate GPS collar or tag.
How Much Does Microchipping a Cat Cost?
- US: usually about $25–75 at a vet clinic, often including registration. Many shelters and low-cost clinics offer microchipping for less, especially at special events.
- UK: usually about £10–30 at a vet practice. Some charities, such as Cats Protection, offer free or reduced-cost microchipping.
Some registries charge a one-time or annual fee for registration or for updating your details, while others are free. Ask your vet which registry they use and how to update your information.
