Microchipping a dog is a quick, in-office procedure that takes only a few seconds. A veterinarian injects a tiny chip under the skin between the shoulder blades using a hypodermic needle, similar to a routine vaccination. No surgery, no anesthesia, and no stitches required.
What the Chip Looks Like
A pet microchip is roughly the size of a grain of rice, measuring about 0.43 inches long and 0.06 inches wide. It’s encased in biocompatible glass, meaning your dog’s body won’t reject it. Inside that tiny capsule is a radio frequency transponder and an antenna, but no battery and no moving parts. The chip sits dormant under the skin until a scanner activates it.
How the Injection Works
The microchip comes pre-loaded inside a sterile, single-use needle. Most implantation needles are 12 gauge, which is noticeably thicker than a standard vaccination needle. Some newer, slimmer chip designs use a 14 gauge needle instead, which reduces the force needed to penetrate the skin. Either way, the vet pinches the loose skin between your dog’s shoulder blades, inserts the needle, and depresses the plunger. The whole process is over in a matter of seconds.
The American Veterinary Medical Association confirms that the pain level is comparable to a typical injection, just with a slightly larger needle. Most dogs react no more than they would to a standard vaccine. No anesthesia is needed, though if your dog is already going under for a spay, neuter, or other surgery, many vets will implant the chip while the animal is sedated as a convenience.
How the Chip Identifies Your Dog
Pet microchips are passive devices. They have no internal power source and don’t emit any signal on their own. When a scanner is held near your dog’s shoulder blades, it sends out a low-frequency radio signal. The chip harvests just enough energy from that signal to power up momentarily and transmit back its unique identification number, typically a 15-digit code. The scanner displays that number on its screen.
The international standards governing pet microchips (known as ISO 11784 and ISO 11785) ensure that chips and scanners from different manufacturers can communicate with each other. These standards were developed specifically so a dog microchipped in one country can be identified in another. The first three digits of the 15-digit ID number identify the chip’s manufacturer, while the remaining digits are unique to your pet. To be sold commercially, chips must pass conformance testing through the International Committee for Animal Recording.
The chip itself does not store your name, address, or phone number. It only contains that ID number. Your contact information lives in a separate online database, which is why registration after implantation is essential.
Registering the Chip
Implanting the chip is only half the job. Without registering the chip’s ID number in a recovery database linked to your contact information, the chip is effectively useless. After the procedure, your vet will give you the chip number and direct you to the appropriate registry. Several companies operate pet microchip databases, and the American Animal Hospital Association maintains a universal lookup tool that searches across registries.
If you move or change your phone number, you need to update the registry. This is the most common reason microchips fail to reunite lost dogs with their owners: not a chip malfunction, but outdated contact details. Some registries charge a one-time fee, while others require an annual subscription that averages about $20 per year. Dogs adopted from shelters typically come already microchipped, with the cost folded into the adoption fee, though you may still need to pay separately to register your own contact details in the database.
Risks and Complications
Microchipping is considered extremely low-risk. The most studied complication is chip migration, where the chip shifts from its original position between the shoulder blades to somewhere else under the skin. A study of dogs and cats entering RSPCA Queensland shelters found a migration rate of 0.8%, consistent with broader research showing rates between 0% and 1.6%. A migrated chip still works perfectly fine. It just means a scanner operator may need to sweep a wider area to find it, which is why shelters and vets typically scan a dog’s entire body rather than only the shoulder region.
Infection at the injection site is possible but rare, comparable to the risk from any needle injection. There’s no ongoing discomfort from the chip once it’s in place, and the biocompatible glass casing prevents tissue reactions in the vast majority of animals.
What It Costs
Microchipping a dog typically costs between $25 and $60 at a veterinary clinic, a price that usually covers both the chip and the procedure. Municipal shelters often charge less. Shelters in cities like Houston and Los Angeles offer microchipping for as little as $15, and some local animal welfare agencies provide the service for free during community events. If you’re getting the chip at a vet’s office, ask whether the quoted price includes database registration or if that’s a separate charge.
What a Microchip Does Not Do
A microchip is not a GPS tracker. It cannot tell you where your dog is in real time. It only works when a scanner is held within a few inches of the chip. Its purpose is identification, not location. If your lost dog ends up at a shelter, vet clinic, or animal control office, the staff will scan for a chip, pull up the ID number, search the registry, and contact you. That chain only works if the chip is registered and your information is current.