Microchipping Your Dog

A microchip is the single most effective way to permanently identify your dog and reconnect with them if you are ever separated. Collars and tags fall off. Microchips do not.

Despite being one of the simplest and most affordable preventive steps a dog owner can take, many dogs are still not microchipped — and of those that are, many are registered to outdated contact information, which defeats the purpose entirely.

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## What a Microchip Is

A microchip is a passive radio-frequency identification (RFID) chip about the size of a grain of rice. It contains a unique identification number — nothing more. No GPS. No battery. No personal information stored on the chip itself.

When a scanner is passed over the chip, it emits a radio frequency that activates the chip long enough to transmit its number. That number is then looked up in a database to find the owner's contact information.

The chip is implanted by injection, typically between the shoulder blades. The procedure takes seconds and is comparable in sensation to a routine vaccination. Most dogs barely react.

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## How the Lookup System Works — and Where It Gets Complicated

Unlike some countries that use a single national database, the United States has multiple competing microchip registries. This means the chip number needs to be registered in a database that shelters and vets actually search.

The major registries include:
- **HomeAgain** — one of the largest in the US
- **AKC Reunite** — widely used
- **Found Animals** — free lifetime registration
- **PetLink**
- **24PetWatch**

**The critical step most people miss:** Getting your dog chipped is only half the job. The chip must be registered in a database with your current contact information. Many chips are implanted but never registered, or are registered but the owner moves and never updates the address.

**Universal lookup tools:** AAHA (American Animal Hospital Association) maintains a universal microchip lookup tool at lookup.aaha.org that searches multiple databases simultaneously. Shelters and vets use this when they find a chipped animal.

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## Chip Standards

Two frequencies are used in North American microchips: 125 kHz (older standard) and 134.2 kHz (ISO international standard). Most modern scanners are universal and read both. If your dog has an older chip, confirm your vet can read it with a current scanner.

International travelers should note that some countries require ISO 134.2 kHz chips for legal entry. If you plan to travel internationally with your dog, confirm chip frequency compatibility before you go.

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## For Guide and Service Dogs

Guide and service dogs should be microchipped without exception. A working dog separated from their handler is both a lost dog and a lost mobility or medical aid device. The faster the reunion, the better for both.

Some guide dog programs chip dogs before placement. Confirm with your program whether the chip is registered to you or to the program, and whether you need to update registration upon retirement or transfer.

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## Keeping Registration Current

Every time you move, change your phone number, or change your email address, update your microchip registration. It takes five minutes and can make the difference between a same-day reunion and a dog who is never identified.

Registration is typically free or low-cost. Found Animals offers lifetime free registration. HomeAgain has an annual fee for enhanced services but the basic lookup is free.

Also register in multiple databases if possible. Cross-registry registration costs nothing and increases the chance of a match if a shelter searches a database you are not in.

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## At the Vet

Ask your vet to scan for your dog's microchip at every annual exam. This confirms the chip is still readable and correctly placed. Chips rarely migrate significantly, but confirming function annually is good practice.

If you adopt a dog and are told they are chipped, have the chip scanned immediately and verify the registration is transferred to your name and contact information. Previous owners can remain in the database if the transfer is not completed.