Pet Microchip Lookup: How It Works and How to Check

How Pet Microchips Work

A pet microchip is a passive RFID (radio frequency identification) device about the size of a grain of rice. It is implanted under the skin between the shoulder blades by a vet or shelter using a needle — no anesthesia needed. The chip itself has no battery and cannot track location. It simply stores a unique 15-digit number.

When a vet, shelter, or animal control officer scans a found pet with a chip reader, the scanner reads that number. The number is then looked up in a microchip registry, which matches the chip number to the registered owner's contact information. This is how reunions happen.

The Problem: Multiple Incompatible Registries

The US does not have a single national pet microchip registry. There are dozens of private registries, and a chip registered in one may not be findable in another. This is why a chip alone is not enough — you need to verify your chip number is in a major registry (or ideally, multiple registries) with current contact information.

How to Look Up a Microchip

Step 1: Use the Universal Lookup First

AAHA Universal Pet Microchip Lookup: petmicrochiplookup.org
This free tool searches 25+ US registries simultaneously with one chip number query. It was developed by the American Animal Hospital Association (AAHA) and is the standard starting point for any microchip lookup. Enter the 15-digit chip number and it will tell you which registries have it on file and whether contact information is registered.

Step 2: Check the Major Registries Directly

• HomeAgain: homeagain.com — One of the largest US registries. Also provides a 24/7 lost pet reporting hotline.
• PetLink: petlink.net — Widely used by veterinary practices and shelters. Free basic registration.
• Found Animals Registry: foundanimals.org — Free registry, widely adopted by shelters.
• AKC Reunite: akcreunite.org — Large registry, also covers cats. 24/7 recovery specialist line.
• 24PetWatch: 24petwatch.com — Commonly used for shelter-adopted pets.

Step 3: If Your Pet Is Already Lost

If your pet is missing right now and you're not sure which registry your chip is in, use the AAHA universal lookup to find out. Then call that registry directly to make sure your contact information is current. Update it if your phone number or address has changed since you registered.

Getting a Microchip Implanted

If your pet is not yet microchipped, the process is quick and affordable:

• Any veterinary clinic can implant a chip during a routine visit — no anesthesia needed
• Many animal shelters offer low-cost or free microchipping events — check your local shelter's website or social media
• Cost ranges from $25–$50 at a vet; often free or $10–$15 at shelter events
• After implantation, register the chip number immediately in at least one major registry — the chip is not automatically registered when implanted

Frequently Asked Questions