How Pet Microchipping Works and Why Every Pet Needs One
Every year, millions of pets become separated from their families. Collars fall off, tags fade, gates are left open. The difference between a temporary separation and a permanent one is often a single factor: whether the pet has a microchip.
Microchipping is one of the simplest, most affordable, and most permanent forms of pet identification available. Despite this, a significant percentage of pets remain unregistered. This guide explains how microchipping works, how much it costs, what you need to do to make it effective, and why it is worth it.
What Is a Microchip?
A pet microchip is a tiny passive RFID (Radio Frequency Identification) transponder, roughly the size of a grain of rice. It has no battery or moving parts. It contains a unique identification number — typically 15 digits in the internationally standardized ISO 11784/11785 format.
The chip is encased in a biocompatible glass capsule. It is inert and does not emit any signal until activated by a scanner.
How Is It Implanted?
A microchip is injected under the skin using a needle — most commonly between the shoulder blades — in a procedure that takes less than a minute. No anesthesia is required. The injection feels similar to a standard vaccine shot and causes minimal discomfort.
The chip is stable and does not move significantly once the surrounding tissue grows around it. Rarely (in less than 1% of cases), chips can migrate a short distance from the implantation site — this is why shelters scan the entire body, not just the shoulder area.
The procedure can be performed by a veterinarian or a trained veterinary technician. Many shelters implant chips routinely before adoption. Some low-cost clinics, pet stores, and community events offer microchipping for $15-$25.
How Does the Microchip Help Find a Lost Pet?
When a lost pet is brought to a shelter, veterinary clinic, or animal control facility, staff scan the animal with a universal microchip scanner. The scanner activates the chip, reads the unique ID number, and that number is searched in pet recovery databases.
If the chip number is registered in the database with current owner information, the shelter can contact the owner directly. The pet is reunited.
If the number is not registered, or if the registered contact information is outdated, the chip number alone cannot identify the owner. The chip is only as useful as the registration attached to it.
The Registration Step Is Mandatory
This is the most common failure point. Many pet owners have their pet microchipped and believe the work is done. It is not. The chip number must be registered in a searchable database linked to current owner contact information.
There are multiple microchip registries in the United States, which creates fragmentation:
- HomeAgain
- AKC Reunite
- Found Animals (free registry)
- PetLink
- AVID
- 24PetWatch
The American Animal Hospital Association (AAHA) maintains the Universal Pet Microchip Lookup Tool (petmicrochiplookup.org), which searches multiple databases simultaneously. This is the tool most shelters and veterinarians use first when a stray comes in.
Steps to complete registration:
- Get your chip number from the implanting vet or on the registration paperwork given at implant.
- Go to petmicrochiplookup.org and search the number to see which registries it is already in.
- Register in at least one database — preferably a universal one. Found Animals offers lifetime registration for free.
- Update your contact information whenever it changes — new phone number, new address, new email.
What a Microchip Cannot Do
A microchip is not a GPS tracker. It does not tell you where your pet is in real time. It only identifies your pet when a scanner is brought to the chip.
A GPS tracker (attached to the collar or incorporated into a smart collar) does provide real-time location and is a useful complement to a microchip — but not a replacement for one. Collars can be removed; microchips cannot.
Microchip vs. Tags
Tags are visible, immediate identification. Anyone who finds a pet can read a tag and call the owner without needing equipment. Tags should be on every pet at all times.
But tags fall off, fade, and are removed. A pet adopted into a different home may have old tags removed by a new owner who does not know about the original family. A chip is permanent.
The combination of a collar with current ID tags and a registered microchip is the most robust identification system available.
Cost of Microchipping
The typical cost of microchip implantation by a veterinarian is $25 to $60, which usually includes registration in the practice’s database or a brief registration period. Low-cost clinics and community events often charge less.
Some chip registries charge a one-time or annual fee for registration. Found Animals offers free lifetime registration. HomeAgain charges an annual fee for premium services but allows free basic lookup.
Lifetime registration for your pet’s chip in a reliable database should not cost more than $20-$30 as a one-time payment.
Ensuring the Chip Is Working
At each annual veterinary exam, ask the veterinarian to scan your pet’s microchip to confirm it is still readable and present. This takes 30 seconds with a scanner and provides peace of mind. Note the chip number in your records.
What to Do If Your Pet Is Lost
If your pet goes missing:
- File a report with local animal control, shelters, and humane societies immediately. Most reunions happen within 5 miles of the home.
- Post in local Facebook and NextDoor groups with photos, your chip number, and contact information.
- Contact your chip registry and report the pet as missing — some registries will send alerts to shelters.
- Provide your chip number to every shelter when you call.
If you find a lost pet:
- Take them to any veterinarian or shelter to scan for a chip.
- The scan is free and takes 30 seconds.
- Even if the pet appears to have a collar and tags, scan for a chip — the tag information may be outdated.
The Bottom Line
A microchip is a one-time investment of $25-$60 that can mean the difference between losing a pet forever and being reunited. It is the most permanent, tamper-proof identification option available. Combined with a registered database entry with current contact information and an ID tag on the collar, it gives your pet the best possible chance of coming home.
If your pet is not yet microchipped, schedule it at your next veterinary appointment. If they are chipped, check that the registration is current. It takes five minutes and is one of the most important things you can do.