Dog Microchipping in the UK: Everything You Need to Know
Microchipping your dog is not optional in the UK — it is the law. Since April 2016, all dogs in England, Scotland and Wales have been required by law to be microchipped and registered on an approved database before they reach eight weeks of age. Owners who fail to comply face a fine of up to £500. Despite this, a significant number of dogs in the UK remain either unchipped or registered on outdated databases, reducing the chance of reunion if they go missing.
What Is a Microchip and How Does It Work?
A microchip is a tiny electronic device, roughly the size of a grain of rice, that is implanted under the skin using a hollow needle. It contains no battery and is entirely passive — it does not transmit any signal on its own. When a compatible scanner is passed over the chip, the scanner emits a radio frequency signal that powers the chip momentarily and reads the unique 15-digit identification number stored within it.
That number is then checked against a microchip database, which should contain the owner's contact details linked to that specific number. The chip itself holds no personal information — only the number. This is why keeping your database record up to date is just as important as having the chip implanted in the first place.
The ISO Standard: Why It Matters
All microchips implanted in the UK must comply with the ISO 11784/11785 standard. This international standard specifies the 15-digit format and the 134.2 kHz frequency at which the chip operates. Compliance with the ISO standard ensures that a chip implanted in the UK can be read by scanners used by vets, rescue centres and local authorities across Europe and in many other countries.
Older chips from some US-based brands such as AVID and Home Again operate at different frequencies (125 kHz or 128 kHz) and are not readable by standard ISO scanners unless the scanner is a universal multi-frequency model. If your dog was microchipped in the United States or another country before arriving in the UK, it is worth having the chip checked by your vet to confirm it is ISO-compliant. For international travel, ISO 15-digit chips are a requirement for entry into most countries, including EU member states.
Proper Scanning Technique: The Cross-Shaped Scan
One of the most common reasons a microchip fails to be detected is poor scanning technique. Because chips can migrate from their original implantation site over time, a scanner held in a single position may miss the chip entirely. Correct scanning involves moving the scanner in a cross-shaped pattern across the dog's entire back, from the neck to the tail and then side to side across the shoulders.
The scanner should be held close to the skin and moved slowly. Rushing the scan is a frequent cause of missed reads. If a chip cannot be found, it does not necessarily mean the dog is unchipped — it may mean the scan was not thorough enough, or the chip has migrated significantly.
Chip Migration: What It Is and What to Do
Microchips are typically implanted at the back of the neck, between the shoulder blades. However, over time a chip can move — sometimes a short distance, sometimes considerably further down the back, along the side of the body, or even down a leg. This is known as chip migration and is more common than many owners realise.
Migration does not usually affect the chip's function, but it can make it harder to locate. If your vet or a rescue centre cannot find your dog's chip, ask them to scan the entire body methodically using the cross-shaped technique before concluding the chip is absent. In rare cases, a chip may fail electronically, in which case re-chipping is recommended.
You can ask your vet to check your dog's chip location at each annual health visit. This takes only seconds and ensures the chip can be found quickly in an emergency.
Keeping Your Registration Up to Date
This is the area where many dog owners fall short. The chip itself is permanent, but the database record is only as useful as its accuracy. If you move house, change your phone number or email address, or transfer ownership of your dog, you must update the relevant database. Failure to do so means that even if your dog is found and scanned, the contact details on record will be wrong and reunion may be delayed or impossible.
In the UK, several approved microchip databases are authorised to hold dog registration records. The main ones include:
- Petlog (run by The Kennel Club)
- Microchip Central
- Dog Lost
- PetDatabase
- Animal Microchips
The government's Check a Pet microchip lookup service at checker.microchipcentral.com allows anyone to search multiple databases using a chip number. However, updating your record must be done directly with the specific database on which your dog is registered. Some databases charge a small administration fee for updates or transfers of ownership.
When you rehome or sell a dog, the microchip registration must be transferred to the new owner. The previous owner should not remain listed as the registered keeper. Both parties should ensure the transfer is completed promptly.
Microchipping and International Travel
If you plan to travel abroad with your dog, the microchip is the first requirement to address. To enter EU countries and many others, your dog must be microchipped with an ISO-compliant 15-digit chip before receiving a rabies vaccination. The order matters: if your dog was vaccinated before being chipped, the vaccination may not be recognised and they may need to be revaccinated.
For travel to certain countries outside the EU, additional requirements such as a rabies blood titre test may apply. These must be carried out after the rabies vaccination and before travel, with the required waiting period observed. Your vet or the APHA (Animal and Plant Health Agency) can advise on the specific requirements for your destination country.
Who Can Implant a Microchip?
In the UK, microchips can be implanted by a vet or by a trained implanter who has completed an approved course. Many rescue organisations, dog wardens and breed clubs offer microchipping at low cost or even free of charge during community events. The procedure is quick, causes minimal discomfort and does not require sedation in most dogs.
Puppies must be microchipped before they are sold or given away, and the breeder must be registered as the first keeper on the database. When the puppy goes to its new home, the registration should be transferred to the new owner. This is a legal obligation, not optional.
What to Do If Your Dog Goes Missing
If your dog goes missing, contact your microchip database immediately to flag the chip as lost, so that any vet or scanner who reads it is alerted. Also report the loss to your local dog warden, nearby rescue centres and vet practices. Websites such as Doglost.co.uk allow you to register a missing dog and alert local volunteers.
A microchip is only as effective as the record behind it. Taking five minutes to verify your contact details are current on your dog's database could make all the difference in the event they go missing.