The pet microchip lookup guide explains how to search for a found pet's chip number across all major US registries — and how to register or update your own pet's chip to keep contact information current. A microchip is only useful if it's registered.
Step 1: Scan the Chip First
Before any lookup, you need the chip number. Microchips cannot be read by smartphones — take the found pet to any veterinary clinic or animal shelter to get a free scan. Most will scan walk-ins for free.
Step 2: Look Up the Chip Number
Search registries in this order — start with the universal lookup before trying individual registries.
Step 3: Register or Update Your Pet's Chip
Even if your vet microchipped your pet, registration is a separate step you must do yourself. The vet inserts the chip — you (the owner) register it with your contact info.
Microchip Number Formats
| Format | Digits | Common Use |
|---|---|---|
| 9-digit | 9 | Older US chips (pre-2007) |
| 10-digit | 10 | Avid brand chips |
| 15-digit ISO | 15 | Current standard, all modern chips |
How to Use the Pet Microchip Lookup System
Microchips are passive RFID transponders — they have no battery and do nothing unless a scanner activates them. The chip stores only a unique number (9, 10, or 15 digits). That number is only useful if it's been registered in a searchable database with the owner's current contact details.
Step 1: Get the Chip Number Professionally Scanned
Any AVID or ISO-compatible universal scanner can read chips. Veterinary clinics and shelters typically offer free scanning. Some shelters have found-pet intake procedures that include scanning and lookup. If a pet has two chips (some imported animals do), both will be detected by a competent scanner — mention this possibility if the first scan finds a chip registered to a country outside the US.
Step 2: Run the AAHA Universal Lookup First
The AAHA Universal Pet Microchip Lookup (lookup.aaha.org) is the single best starting point — it queries multiple registries in one search. Enter the chip number exactly as written. If the lookup returns "chip found, not registered," the chip exists but the owner never completed registration. In that case, contact local shelters with the chip number and use social media lost-pet groups.
Step 3: Check Individual Registries if Universal Lookup Misses
Not all registries participate in universal lookups. Check AKC Reunite (akcrcar.org), HomeAgain (homeagain.com), PetLink (petlink.net), 24PetWatch (24petwatch.com), and Found Animals (foundanimals.org) individually. Each has a chip number search field. Some charge for detailed contact info lookup — contact local animal control if you hit a paywall.
Step 4: Register Your Own Pet in Multiple Registries
Found Animals Registry (foundanimals.org) offers completely free lifetime registration. AKC Reunite offers a one-time fee with good national reach. HomeAgain includes annual membership perks beyond chip lookup. Register in at least two registries and verify your data annually — particularly after address or phone number changes, which are the most common reason reunions fail.
FAQ
Is this pet microchip guide free?
Yes, completely free with no signup required.
How do I look up a found pet's microchip number?
Start with the AAHA Universal Pet Microchip Lookup at lookup.aaha.org — it searches multiple registries simultaneously. Enter the 9, 10, or 15-digit chip number found by scanning. If no result, try individual registry lookups: AKC Reunite, HomeAgain, 24PetWatch, and PetLink. Always bring the pet to a shelter or vet for a chip scan first.
What if the chip lookup shows no registration?
An unregistered chip still means the chip exists — the pet was microchipped but the owner never registered or the registration lapsed. Note the chip number and contact local shelters, veterinary clinics, and lost pet groups in your area with that number. Some vets keep internal chip records. Post to Nextdoor and Facebook with the chip number visible.
Do I need to pay to register a pet microchip?
Some registries charge fees, others are free. AKC Reunite charges a one-time registration fee. HomeAgain has annual membership plans. PetLink and Found Animals are free. The AAHA Universal Lookup searches paid and free registries together. Registering in a free registry is better than not registering at all.
My pet is already chipped — how do I check the registration is current?
Look up your pet's chip number at lookup.aaha.org. If your contact info appears and is current, you're set. If it shows no registration or old contact info, contact the registry directly or register your chip in a free registry like Found Animals (foundanimals.org/chip-registry/). Always update your registration when you move or change phone numbers.
Can microchips be read by all scanners?
Modern universal scanners can read 125 kHz, 128 kHz, and 134.2 kHz chips. Older scanners could only read certain frequencies. If a shelter says a chip can't be read, ask them to try a different scanner. All chips implanted in the US since 2007 should be readable by any ISO-compliant universal scanner.