The short answer
Hotel key cards usually stop working because the stay data has expired or been replaced, a magnetic stripe has been erased by a magnet or worn by swiping, an RFID card has been bent and its antenna damaged, or the lock or encoder has a problem such as a low battery. Many are fixed by simply re-encoding the card.
The common causes, by card type
Start with the card type. A magnetic stripe card and an RFID key card fail in different ways, and some problems sit with the lock or encoder rather than the card. Our guide to RFID vs magnetic stripe key cards explains how each type is read.
Magnetic stripe cards
The stripe has been demagnetized
Strong magnets can erase or scramble a stripe. The usual culprits are magnetic clasps on phone cases, wallets and bags. HiCo stripes (2750 Oe on our cards) resist accidental erasure better than LoCo stripes (300 Oe).
The stripe is worn or scratched
Every swipe passes the stripe over a read head. Over time, scratches and wear make the recorded data harder to read, and the card fails intermittently before it fails completely.
The stripe does not match the encoder
If a new batch of cards has a different coercivity from the one your encoder writes, the cards may encode badly or not at all. Check the encoder setting, or send us a card you use today so we match it.
RFID cards
The stay has ended or been replaced
The encoder writes a checkout date and time onto the card, and the lock refuses it afterwards. On many systems, encoding a new key for the same room also cancels earlier keys, so a guest holding an old card is locked out after a room move or extension.
The chip is not the one the lock expects
After a lock replacement or software change, locks may read a different chip or different chip settings. Cards ordered to the old specification then fail at the door. Our guide to MIFARE Classic vs Ultralight explains the common hotel chips.
The antenna is damaged
An RFID card has a thin antenna running around its edge. Sharp bending, cracking or punching a hole in the wrong place can break it, and the chip then cannot be powered or read.
The card is held with other contactless cards
A key card pressed against other contactless cards can make the read unreliable. Holding the key card on its own, flat to the reader, rules this out.
Lock and encoder causes
The lock battery is low
Most guest room locks run on batteries. As they run down, a lock can become slow or unreliable, and good cards appear to fail on one door only.
The encoder wrote the card incorrectly
A wrong room number or date at check-in, a card lifted off the encoder too early, or an encoder fault produces a card that looks fine but holds the wrong data.
The lock settings are out of step
A lock's clock or settings can drift out of step with the front desk system. If cards fail only on certain doors, your lock vendor can check those locks.
What the front desk can check
A short routine separates card faults from lock faults and saves guests a second trip to the desk.
Check the stay on the system
Confirm the room number, checkout date and time, and whether a newer key has been issued for the same room.
Re-encode the same card
Many failures are data problems. Re-encoding the card the guest already has fixes expired stays, cancelled keys and encoding errors.
Try a fresh card
If the re-encoded card still fails, encode a new one. If the new card works, retire the old one: it may be demagnetized, worn, bent or damaged.
Test the door with a known good card
If a fresh card fails on one door but works on others, the problem is likely the lock. Note the room and ask maintenance to check the battery.
Keep a note of the pattern
Record which rooms and which batches of cards fail. Failures across a whole batch point to the cards; failures on a few doors point to the locks.
If you suspect a lock or encoder fault, contact your lock vendor. They can check lock batteries, settings and encoder configuration for your system.
When to change your cards
Re-encoding fixes most problems. New cards are the answer when the cards themselves, rather than the data on them, are the problem:
- Your locks or lock software have changed. Confirm which chip the new setup reads before reordering. Our lock compatibility guide explains how to find out what you have.
- A whole batch fails. If cards from one order fail across many doors, the chip or stripe may not match your system. Send us a working card and one that fails, and we read both.
- Stripe cards keep demagnetizing. HiCo stripes resist erasure better than LoCo, but they must match what your encoder writes. Moving to RFID removes the stripe altogether; dual-technology cards help during the changeover.
- Cards are visibly worn, cracked or bent. Retire them rather than re-encoding them again.
Before a new order, we send blank test cards with the chip we propose, so you can encode them and try them on your own doors first. During production, chips are read-tested before packing, so you do not find a dead card at the front desk. For a wider view of keys for your property, see hotels and resorts.
Questions buyers ask
Can a phone demagnetize a hotel key card?
It can happen with magnetic stripe cards, though the usual cause is a magnet near the phone, such as a magnetic case clasp or wallet, rather than the phone itself. RFID cards store data in a chip, so magnets do not erase them.
Do we need a new encoder if our cards keep failing?
Usually not. Cards with the right chip work with the encoder you already have. If cards fail after encoding even when they are new and undamaged, ask your lock vendor to check the encoder, and send us a sample card so we can confirm the chip matches.
