Microchipping a Dog (and Cat): The UK Law Explained

Microchipping is one of the few bits of pet health admin that isn't a choice — it's the law. The good news is it's quick, lasts a lifetime, and dramatically improves the odds of being reunited with your pet if they ever go missing. Here's what UK owners need to know.

This is general guidance, not a substitute for veterinary or legal advice — check with your vet if you're unsure about your responsibilities.

What microchipping is

A microchip is a tiny device, about the size of a grain of rice, inserted under the loose skin between your pet's shoulder blades. It carries a unique number that's stored on a national database alongside your contact details. If your pet is found and scanned — by a vet, rescue centre or warden — that number brings up your details so you can be reunited. The chip doesn't track your pet's location like a GPS tracker; it only works when someone scans it.

The UK law — dogs AND cats

This is the important bit, and it's where a lot of owners are out of date:

• Dogs must be microchipped by law in the UK. Dogs need to be chipped by eight weeks of age, and your contact details on the database must be kept up to date.
• Cats must now be microchipped too. The law changed so that, from 10 June 2024, owned cats in England must be microchipped by twenty weeks of age. This is a relatively new requirement, so if you've had your cat a while, do check they're chipped and that your details are current.

Keeping your registered details up to date is part of the legal requirement — a chip is only useful if it points to the right phone number and address. If you move house or change your number, update the database. Failing to comply can lead to a notice to get your pet chipped and, ultimately, a fine.

Why it matters

Collars and tags fall off; microchips don't. A chipped pet with up-to-date details is far more likely to be reunited with their owner quickly, and it's a permanent, tamper-resistant proof of ownership. For cats in particular — who roam and sometimes get taken in elsewhere by mistake — it's invaluable. It also helps reunite pets after road accidents, where every minute counts.

What to expect

The chip is usually inserted by a vet, nurse or trained implanter using a needle, much like a vaccination. It takes seconds, and most pets barely react. It's often done at the same time as a vaccination appointment or during neutering, which is convenient. Afterwards there's nothing to maintain — but do make a note to keep your database details current, and ask your vet to scan the chip at routine check-ups to confirm it's still readable and hasn't migrated.

Keeping details up to date

When you get a pet, make sure the chip is registered to you, not just to the breeder, rescue or previous owner. There's usually a small fee to transfer or update records on the database, but it's well worth it. If you're not sure who your pet's chip is registered with, your vet can scan the chip and help you find the database, then you can update it directly.

Microchip versus collar tag — you need both

A microchip doesn't replace a collar and tag. In fact, the law requires most dogs to wear a collar with an ID tag bearing the owner's name and address when out in a public place — that's a separate, long-standing requirement from microchipping. Think of them as belt and braces: the tag means anyone who finds your dog can call you straight away without needing a scanner, while the chip is the permanent backup that can't fall off or be removed. Cats can't safely wear ordinary collars (always use a quick-release safety collar if you use one at all), which is part of why the microchip law for cats matters so much.

What happens if my pet goes missing?

If your microchipped pet is found and handed to a vet, rescue or warden, the first thing they'll do is scan for a chip. The number that comes up is checked against the database, and you're contacted using your registered details. This is exactly why keeping those details current is so important — and why it's worth registering your own number plus an emergency backup contact if the database allows it. If your pet does go missing, report it to the microchip database, your local council, and nearby vets and rescues, and they'll be on the lookout when a scan comes up.

Common worries

Owners sometimes worry the chip will hurt, move around, or cause health problems. Insertion is quick and similar to a vaccination, the chip is designed to stay put (your vet can check its position at check-ups), and serious problems are very rare. The benefits — a permanent, legal, reunite-your-pet safety net — far outweigh the tiny risks. If you ever have concerns, your vet is the right person to ask.

Costs

Microchipping is inexpensive compared with most pet procedures, and it's often included free or at low cost when you rehome from a rescue, or bundled into a first vaccination or neutering visit. Some charities and councils run free or low-cost microchipping events. Prices vary, so ask your vet or local rescue. Use the wider puppy cost calculator to fold it into your first-year budget, and keep all your pet's health dates together with the pet medicine calendar and vaccine reminder.

Need a vet or scanner? Try our vets directory. For the rest of the new-pet admin, see puppy vaccinations, kitten vaccinations and our kitten hub.

Sources

• GOV.UK — Get your dog or cat microchipped
• Cats Protection — Microchipping
• PDSA — Microchipping
• RSPCA — Microchipping