How Microchips Help Find Lost Pets
A chip only works if the record behind it does. See how a scan leads back to you, and why keeping your details current makes all the difference.
If your pet goes missing, their microchip is often what leads a finder back to you. The chip itself holds a number which links to the owner’s contact details on a database — but it only works if the details are yours and current.
How do microchips work in dogs and cats?
A microchip is a tiny device the size of a grain of rice, implanted under the skin between the shoulder blades. It’s a one-off purchase that lasts your pet’s lifetime.
The chip holds a 15-digit number that a scanner reads. There’s no name, address or phone number on it, and it isn’t a tracker. Those details sit on a database, linked to the number.
Microchips work the same way in both species. Chipping takes a few seconds either way, through a quick injection.
Dogs have had to be microchipped since April 2016 in England, Wales and Scotland. In Northern Ireland, a dog needs a licence from its district council, and the council won’t issue one unless the dog is chipped. A dog in England, Wales or Scotland must also wear a collar and tag with your name and address when out in public, chip or no chip.
Cats have had to be microchipped in England since June 2024. In Scotland, Wales and Northern Ireland, chipping a cat is optional, though it works exactly the same if you do. Cats Protection reports that 73% of UK cats are chipped in 2026, down from 74% in 2025.
In the England regulations, “microchipped” means two things together: a compliant chip implanted, and the details recorded on a compliant database. A chip with no registration doesn’t count. That applies to cats just as much as dogs. The chip is only half the job.
From found to home
If your pet goes missing but is found, this is the chain a microchip record travels down:
- Someone finds your pet and takes them to a vet, rescue centre or dog warden, who can scan them for the number.
- The scan turns up the chip’s number.
- The number is looked up to find which database holds the record. Our chip checker searches multiple UK databases at once and shows whether the number is registered and where.
- The database holds your details. In England, the record must include your full name, address and phone number, plus your pet’s description, date of birth and chip number.
- On Pet Database, the vet, warden or rescue who has your pet can reach you through the record, and your private contact details are never shown to the public. In England, databases must answer enquiries by phone and online at any hour, and pass on any enquiry about a chip registered elsewhere.
While you’re waiting for that call, you can help the chain along. Mark your pet as missing on the database — reporting a pet missing on Pet Database is free. Our guide to what to do in the first hour covers the rest of the early steps.
There isn’t one national database. GOV.UK lists 25 databases that meet government standards, and Pet Database is one of them. If you’ve found a pet yourself, our guide to what to do when you find a dog covers who to call.
Why the record matters as much as the chip
Every step above depends on one thing: the details on the database being yours, and being current.
Battersea Dogs and Cats Home’s 2026 stray dog report found that of strays microchipped in full compliance, 84% were reunited with their owner. Of strays with no chip at all, 19% were.
The same report found the two ways it breaks down. 34% of strays had a chip whose record hadn’t been updated with the current owner’s details, up from 30% in 2023, and 14% had a chip not registered on a compliant database.
One more caution: emails from any database outside the government list asking for money to register your pet could be a scam. Our guide to mistakes that delay finding a lost pet covers the other ways reunions stall.
So keep the record current. You’re responsible for keeping your details up to date, for example when you move house. When a pet changes owner, in England the new owner must record their own contact details on the database, unless the previous owner already has. Databases are allowed to charge for updates, but Pet Database is free.
Common questions
Can a microchip move?
Yes, a little. Chips commonly shift a small distance from where they were implanted. It doesn’t hurt, very rarely causes problems, and the chip will still be picked up when scanned. It’s one reason a scan sweeps from the shoulder blades toward the base of the tail.
If a chip moves, fails or causes a reaction, in England it must be reported. If a failed chip is replaced, updating the database is the owner’s job.
What if a scanner can’t find or read the chip?
A missing reading doesn’t always mean a missing chip. A chip only counts as a failure if it isn’t detected after a full-body scan with a working scanner. A proper check covers the whole body, not just one spot.
Not every scanner reads every chip type. Some read ISO FDX-B chips only, while others cover more than one frequency. A small number of older chips can’t be read by the UK’s approved scanners at all, in which case the dog has to be rechipped with a compliant device.
If a chip is confirmed as moved, failed or causing a reaction in England, vets and trained implanters report it to Defra using the adverse event form. In Scotland, reports must be made within 21 days of the problem being identified.
What if my pet is found abroad?
The same scan still works, but UK databases don’t search foreign registries, so a foreign number is traced through international tools instead. Our guide to how microchips enable international recovery explains the route.
My pet’s chip is on a different database. Can I move it?
Yes. A chip registered on another database can be moved to Pet Database without your pet being rechipped.
How do I report my pet missing on Pet Database?
You report it through your online account, and the lost pet service starts at no cost. Pet Database sends Safety Pings whenever the chip is searched for, and shares the report across social media.
How do I check a chip number?
Use our chip checker. It’s free and needs no account. It tells you whether the number is registered and which database holds it, so you know where to update the record.
A chip only gets a lost pet home when the record behind it is yours and current. Take a minute to check your pet’s chip record is up to date.
