Microchipping Your Pet: How It Works, Registration and Keeping Details Up to Date
A microchip gives your pet permanent ID, but it only works if the registry has your current phone number and address.
A pet microchip is a tiny implant, about the size of a grain of rice, placed under the skin that stores a unique ID number. When a vet or shelter scans it, they get the number and look it up in a registry database to find you. It is not a GPS tracker and has no battery. A chip only helps if it is registered with your current contact details, so registering and updating it is just as important as getting it implanted.
How a microchip works
- The chip is a passive radio-frequency device. It does nothing until a scanner passes over it and powers it briefly to read the number.
- The number links to your details in a registry, not on the chip itself.
- It is designed to last for your pet’s life.
- It cannot show your pet’s location. For that, you need a separate GPS device; see GPS pet trackers vs. microchips.
The implant
A vet or trained professional injects the chip under the skin, usually between the shoulder blades, using a needle. It is quick, similar to a routine injection, and usually done without anesthesia, though many owners have it done during spay or neuter surgery. Problems such as the chip moving or a local reaction are uncommon. Ask your vet about any concerns for your pet.
Shelter and rescue animals are often chipped before adoption. If you adopt, ask for the chip number and confirm it is transferred to your name.
Registration: the step that matters most
- Get the chip number from your vet, shelter or breeder paperwork.
- Find out which registry the chip is recorded with. In the US, the AAHA Universal Pet Microchip Lookup tool can show which participating registry holds a chip number; it does not show owner details.
- Register or transfer the chip into your name with your phone number, email and address. Some registries charge a fee.
- Add an emergency contact in case you cannot be reached.
- Update after any change: new phone number, move, new email, or rehoming.
- Ask your vet to scan the chip at checkups to make sure it still reads.
Chip standards and scanners
Much of the world uses the international ISO standard (ISO 11784/11785), operating at 134.2 kHz. In the US, chips operating at other frequencies have also been used, so many shelters and vets use universal scanners that read several types. If you plan to travel abroad, check that your pet’s chip meets your destination’s requirements; see taking a pet to another country.
Microchip vs. ID tag vs. GPS
| Option | Strengths | Limits |
|---|---|---|
| Microchip | Permanent; cannot fall off; accepted proof of ID | Needs a scanner; only as good as registry details |
| Collar ID tag | Anyone can read it and call you immediately | Can fall off or be removed |
| GPS tracker | Shows location in real time | Needs charging, often a subscription, and can come off |
Most owners do best with a microchip plus a collar tag, and a GPS device for dogs prone to escaping.
Legal requirements
- England: dogs must be microchipped and registered by 8 weeks old, and since June 10, 2024 cats must be microchipped and registered by 20 weeks old. Keepers must keep database details up to date. Councils can require an unchipped pet to be chipped within 21 days, and owners who do not comply can face a fine of up to £500. See GOV.UK on getting your dog microchipped. Scotland and Wales have their own dog microchipping rules.
- UK collar tags: dogs in public places in Great Britain must also wear a collar with the owner’s name and address, under the Control of Dogs Order 1992.
- US: there is no federal microchip requirement for pets living in the US, but some cities and counties require it, and many shelters chip every animal before adoption. Dogs entering the US must have an ISO-compatible chip under CDC rules.
Common microchip mistakes
- Never registering the chip. Implanting it is only half the job; an unregistered chip may lead only to the manufacturer or the clinic that sold it.
- Old phone numbers. Moving or changing numbers without updating the registry is one of the most common reasons chipped pets are not returned quickly.
- Not transferring ownership. When you adopt or buy a pet, the chip may still be registered to the shelter, breeder or previous owner.
- Assuming it was done. If you are unsure whether your pet has a chip, ask your vet to scan them at the next visit.
If your pet goes missing
Report your pet as lost with the registry immediately and check your details are current. Then follow the steps in how to find a lost pet. The AVMA’s microchip guide explains how chips help reunite pets and families.
Bottom line
A microchip is a simple, permanent backup ID for your pet, but it is only as good as the details in the registry. Get your pet chipped, register it in your name, update it whenever your phone number or address changes, and pair it with a collar tag for the fastest reunions.
FAQ
Does microchipping hurt?
It feels similar to a routine injection, with a slightly larger needle. Most pets react briefly. Your vet can do it during another procedure if you prefer.
Can I track my pet with a microchip?
No. A standard microchip has no GPS or battery. It only provides an ID number when scanned.
How do I find my pet’s microchip number?
Check adoption or vet paperwork, or ask your vet to scan your pet. Then use a lookup tool to find the registry.
Do indoor cats need microchips?
Indoor cats can slip out through open doors or windows. A chip gives them permanent ID, and in England it is a legal requirement for most pet cats.