How to Read Pet Microchip: Easy Steps for Owners

I've spent years volunteering at animal shelters, and one thing I've learned: a microchip is useless if no one can read it. I remember the first time I tried to scan a stray dog — I held the scanner wrong and nearly missed the chip. That mistake cost us hours. Let me walk you through exactly how to read a pet microchip, so you never fumble.

What Is a Pet Microchip & Why Would You Need to Read It?

A pet microchip is a tiny RFID tag (about the size of a grain of rice) implanted under the skin, usually between the shoulder blades. It stores a unique 9- to 15-digit number. No battery, no GPS — just a passive transponder that wakes up when a scanner passes over it.

You'd need to read a microchip if you find a lost pet, adopt a rescue, or buy a used pet that might have one. Shelters and vets scan every animal that comes in. But as a pet owner, you should also know how to check if your own pet's chip is still working or if the number matches your paperwork.

How to Scan a Microchip with a Universal Reader

Most shelters use a universal scanner that reads all common frequencies (125 kHz, 128 kHz, 134.2 kHz). If you're a volunteer or a pet owner with access to one, here's the right technique:

1. Turn on the scanner — wait for the green light or beep.
2. Hold the scanner flat against the pet's skin, not at an angle. Start at the neck and slowly move down to the shoulders.
3. Make slow passes in an S-pattern. Don't rush. The chip can migrate, so scan the entire torso.
4. Listen for a beep — the scanner will emit a tone and display the number on its screen.
5. Repeat if you don't get a read. Older chips or deep placement can require multiple passes.

Universal scanners cost anywhere from $50 to $200. You can buy one online or borrow from a local vet. I always keep a cheap one in my car — invaluable when I spot a stray.

How to Read the Microchip Number

Once the scanner shows a number, write it down exactly as displayed. Microchip numbers are alphanumeric (letters and numbers) or all digits. For example: 985112005678912 (15 digits) or 4A5B3C2D (8 characters).

The number alone doesn't tell you the owner. It's just a serial number assigned by the manufacturer (like Avid, HomeAgain, or 24PetWatch). The first few digits indicate the manufacturer:

But don't rely on the prefix alone. Some manufacturers share prefixes. The only way to guarantee a match is to look up the number in a database.

How to Find the Owner from the Microchip Number

This is the step most people mess up. You don't just Google the number. You need to use a universal pet microchip lookup service. My go-to is the AAHA Universal Pet Microchip Lookup Tool (American Animal Hospital Association). It's free, no registration required.

Steps:

1. Go to the AAHA lookup page (search "AAHA microchip lookup").
2. Enter the full microchip number, no spaces or dashes.
3. The tool tells you which registry holds the owner's contact info (e.g., HomeAgain, PetLink, 24PetWatch).
4. Click the link to that registry's lookup page — you may need to create a free account or call them.
5. If the owner registered their contact, you'll get phone number or email.

What If the Chip Is Not Registered?

You hit a dead end. The AAHA tool says "no registry found" or "registration expired." Here's what I do:

• Try all major registries manually: HomeAgain, 24PetWatch, AKC Reunite, PetLink, Avid. Some registries allow a free search even without an account.
• Call the manufacturer based on the chip prefix. For example, if it starts with 985, call HomeAgain (1-800-424-7387). They might help reunite pets even without a current registration.
• Check with local vets — the chip might have been implanted at a clinic that keeps internal records.
• Post the chip number on social media in lost-pet groups. Sometimes the owner searches the internet for their own chip number.

I once reunited a stray cat because the owner had (luckily) posted the chip number in a Facebook group years ago. Desperate measures, but it works.

Can a Smartphone Read a Pet Microchip?

Short answer: No, not with the phone alone. Smartphones don't have the hardware to read 125 kHz or 134.2 kHz RFID. But you can attach a small external microchip reader to your phone. Devices like the PetScanner or Halo Reader plug into the headphone jack or Lightning port and work with a companion app.

These portable readers are excellent for rescue volunteers. I carry a PetScanner in my glove compartment — it's about the size of a USB stick. The app shows the number and even lets you run a quick lookup. Downside: they only read 134.2 kHz (ISO chips), not older 125 kHz ones. So they're not universal.

If you're serious about field reading, get a universal scanner. For occasional use, a smartphone reader will do — just know its limits.

Frequently Asked Questions