Glossary

Microchip and registry

A rice-sized implant that holds an ID number, which links to your contact details only if you register it; it is not a GPS tracker.

Also called: microchip, pet microchip, microchip registration, chip registry, ISO microchip, microchip number

A microchip is a tiny transponder, about the size of a grain of rice, that a vet or shelter injects under the skin between the shoulder blades. It holds a number, usually 15 digits for the international standard. A scanner reads the number when passed over the dog. The chip has no battery and cannot show where a dog is, so it is not a GPS dog tracker.

The number is useful only if it is linked to a record. The owner must register the number with a registry and keep their phone number and address up to date, and many dogs go home from a animal shelter with a chip that was never registered. Ask who holds the record, check the number with a free online lookup tool and update it when you move.

A microchip is permanent identification, and it complements a collar tag and a dog license.

Last reviewed November 8, 2026

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Related terms

GPS dog tracker A collar-mounted device that uses satellite positioning and a cellular connection to show your dog's location on a phone, usually for a monthly fee. Dog license A local government registration of a dog, often required by law, usually needing proof of rabies vaccination and giving a tag that helps return a lost dog. Animal shelter A facility that houses stray, lost and surrendered dogs and cats, run by a city, county or non-profit, which returns pets to owners or places them in new homes. Adoption fee The payment a shelter or rescue asks when you adopt a dog, helping cover vet care and running costs, often including vaccines, spay or neuter and a microchip.