How Do Microchip Cat Flaps Work? (Complete UK Guide)

A microchip cat flap contains a small RFID reader in the frame. When your cat approaches with their head close to the flap, the reader scans for their existing vet-implanted microchip (the same one your vet scans at appointments). If the chip number matches one stored in the flap's memory, an internal motor releases the latch and your cat pushes through. If not, the flap stays locked.

No collar, no batteries on the cat, no extra hardware — it uses the chip already under your cat's skin.

Three components do all the work:

1. RFID antenna built into the flap frame — typically scans a range of around 5–10 cm.
2. Microprocessor that compares the scanned chip number against the stored 'allowed' list (modern flaps store anywhere from 1 to 32 cats).
3. Electromechanical latch — a small motorised pin that physically blocks the flap from opening unless an authorised chip is detected.

It's all powered by a few AA batteries that last 6–12 months. Some models also offer mains adaptors or USB power.

If your cat doesn't have a vet microchip yet, two options:

1. Get one fitted — it's now a legal requirement in England for cats over 20 weeks old (since 10 June 2024), costs around £15–£30 at a vet, and takes 30 seconds. The chip lasts a lifetime.
2. Use the included RFID collar tag — every major microchip cat flap (SureFlap, PetSafe, Closer Pets) ships with a small RFID disc you can clip to a quick-release collar. Works the same way as a chip read.

Most owners go with the chip — no collar to lose, no clinking, nothing for the cat to chew off.

We fit thousands of these. The four main brands in the UK:

• SureFlap Microchip Cat Flap — Cambridge-designed, the original microchip cat flap (2008). Stores 32 cats. The single most-installed model in Britain.
• SureFlap DualScan — same flap but reads cats coming *in* and *out* separately, so you can keep some cats indoors at night while others come and go.
• SureFlap Microchip Pet Door — larger version for bigger cats and small dogs.
• PetSafe Microchip Cat Flap — strong budget alternative, simpler programming, stores up to 40 cats.
• Closer Pets Microchip Cat Flap — UK-made, sealed against draughts, good for windy or exposed installations.
• SureFlap Connect — adds app control, curfew scheduling and entry/exit logging via a separate hub.

Pros:
• Stops neighbouring cats, strays and wildlife getting in
• No collar needed (no losses, no snags)
• Locks automatically when your cat isn't nearby — useful for security
• Reduces flea risk from visiting cats
• Curfew/DualScan models give fine-grained control per cat

Cons:
• More expensive than manual flaps (typically £80–£170 vs £20–£40)
• Battery dependent — though batteries last most of a year
• Slightly slower than a manual flap (motor takes ~1 second to unlock)
• If your cat's chip has migrated to an awkward spot, occasional misreads can happen

In our experience, yes — extremely. We fit dozens every month and warranty-related callbacks are rare. The most common issue is battery depletion (the flap warns you with a flashing LED), followed occasionally by a chip that's drifted out of normal scanning range.

If the cat refuses to use the new flap, it's almost always a behavioural settling-in issue rather than a fault. We always advise wedging the flap fully open for the first 2–3 days so the cat learns the route without the noise of the motor.

Two parts:

• The cat flap itself: £80–£170 depending on brand and model. We can supply or you can buy your own.
• Fitting: from £60 (UPvc door), £280 (glass door — includes new toughened panel).

See our cost calculator for a tailored estimate, or read our SureFlap installation guide for full details.

Microchip cat flaps use your cat's existing vet microchip and a small RFID reader to keep neighbours' cats and strays out. They're reliable, secure, and now the default choice for most UK homes. SureFlap is the bestseller, PetSafe is the value pick, and Closer Pets is great for exposed installations.

If you'd like one fitted, send us a photo of your door for a quote for your job.