Chips and technology
125 kHz vs 13.56 MHz: proximity and smart cards compared
By James Keltner, Owner · Last reviewed
The short answer
125 kHz (LF) proximity cards usually send a fixed ID number to a nearby reader, with little or no security. 13.56 MHz (HF) smart cards follow ISO/IEC 14443 or 15693, can store and protect data, and include NFC chips that phones read. Your reader decides: a card only works at the frequency your reader uses.
Two frequencies, two kinds of card
Both card types are passive: there is no battery, and the reader's radio field powers the chip for the moment it takes to read it. The difference is the frequency of that field, and what the chip can do once it is powered.
125 kHz (low frequency, LF) is the older proximity technology still used on many staff doors, car parks and gyms. A typical LF proximity chip holds a fixed ID number that the reader looks up in its access list. Some LF chips, such as the EM4200, are read-only; others, such as the T5577, can be written to.
13.56 MHz (high frequency, HF) is the frequency of most smart cards, hotel key cards and NFC tags. Contactless cards at 13.56 MHz follow one of two ISO/IEC families: ISO/IEC 14443 for proximity cards read close to the reader, and ISO/IEC 15693 for vicinity cards read from a little further away. HF chips range from simple ID tags to chips with memory sectors and encryption, such as the MIFARE family and DESFire.
125 kHz and 13.56 MHz compared
125 kHz (LF) proximity cards and 13.56 MHz (HF) smart cards, feature by feature
Standards
- 125 kHz (LF)
- No single ISO card standard; readers are matched to the chip type, such as EM4200 or T5577
- 13.56 MHz (HF)
- ISO/IEC 14443 (proximity) and ISO/IEC 15693 (vicinity)
Read range
- 125 kHz (LF)
- Short: the card is held close to the reader
- 13.56 MHz (HF)
- Short for ISO/IEC 14443 cards; ISO/IEC 15693 vicinity cards are designed to read from further away
What the chip holds
- 125 kHz (LF)
- Usually a fixed ID number; some chips can be rewritten
- 13.56 MHz (HF)
- From an ID number to memory sectors that store access rights, balances or links
Security
- 125 kHz (LF)
- Usually none: the ID number is sent openly
- 13.56 MHz (HF)
- Depends on the chip, from basic ID to chips with encryption such as MIFARE Ultralight C and DESFire
Read by phones?
- 125 kHz (LF)
- No
- 13.56 MHz (HF)
- NFC chips such as NTAG are read by most modern smartphones; other HF chips depend on the phone and app
Typical uses
- 125 kHz (LF)
- Staff doors, gyms, car parks, lockers and older access systems
- 13.56 MHz (HF)
- Hotel room locks, smart cards, cashless payments, NFC tags and newer access systems
| Feature | 125 kHz (LF) | 13.56 MHz (HF) |
|---|---|---|
| Standards | No single ISO card standard; readers are matched to the chip type, such as EM4200 or T5577 | ISO/IEC 14443 (proximity) and ISO/IEC 15693 (vicinity) |
| Read range | Short: the card is held close to the reader | Short for ISO/IEC 14443 cards; ISO/IEC 15693 vicinity cards are designed to read from further away |
| What the chip holds | Usually a fixed ID number; some chips can be rewritten | From an ID number to memory sectors that store access rights, balances or links |
| Security | Usually none: the ID number is sent openly | Depends on the chip, from basic ID to chips with encryption such as MIFARE Ultralight C and DESFire |
| Read by phones? | No | NFC chips such as NTAG are read by most modern smartphones; other HF chips depend on the phone and app |
| Typical uses | Staff doors, gyms, car parks, lockers and older access systems | Hotel room locks, smart cards, cashless payments, NFC tags and newer access systems |
Neither frequency is right for every site. The card has to match the reader, so the first question is always what your locks, doors, lockers or tills already read.
How to tell which frequency you have
Check the reader or lock documentation
The make and model is usually on the reader, the lock face or a label on the encoder. The specification will list 125 kHz, 13.56 MHz or both.
Try a phone
If an NFC-enabled phone reacts when you hold a card to it, the card is 13.56 MHz. If nothing happens, the card may be 125 kHz, or an HF chip the phone does not read.
Send us a card or fob you use today
We read the chip directly and confirm the frequency and chip type before we quote, so the new cards match your system.
If you run both frequencies, for example 125 kHz staff doors and 13.56 MHz guest locks, a dual-frequency card, fob or wristband carries both chips, so one credential works everywhere.
Which of our products use each
Most of our cards, fobs and wristbands can be made at either frequency. The chip is chosen to match your system before anything is printed.
Frequencies available on our products, as listed in each product specification
- 125 kHz (LF)
- Yes
- 13.56 MHz (HF)
- Yes: MIFARE Ultralight, Ultralight C, Mini, Classic 1K and 4K
- Dual frequency
- Not listed
Slot-punched access cards and staff photo ID cards
- 125 kHz (LF)
- Yes
- 13.56 MHz (HF)
- Yes: MIFARE family
- Dual frequency
- Not listed
- 125 kHz (LF)
- No
- 13.56 MHz (HF)
- Yes: MIFARE Classic, Ultralight EV1, DESFire, NTAG (ISO 14443A)
- Dual frequency
- No
- 125 kHz (LF)
- Yes: for example EM4200, T5577
- 13.56 MHz (HF)
- Yes
- Dual frequency
- Yes
Adjustable and classic silicone wristbands
- 125 kHz (LF)
- Yes
- 13.56 MHz (HF)
- Yes
- Dual frequency
- Yes
Tyvek and vinyl single-use wristbands
- 125 kHz (LF)
- No
- 13.56 MHz (HF)
- Yes
- Dual frequency
- No
- 125 kHz (LF)
- Yes
- 13.56 MHz (HF)
- Yes: MIFARE family
- Dual frequency
- Yes
| Product | 125 kHz (LF) | 13.56 MHz (HF) | Dual frequency |
|---|---|---|---|
| RFID hotel key cards | Yes | Yes: MIFARE Ultralight, Ultralight C, Mini, Classic 1K and 4K | Not listed |
| Slot-punched access cards and staff photo ID cards | Yes | Yes: MIFARE family | Not listed |
| NFC and MIFARE smart cards | No | Yes: MIFARE Classic, Ultralight EV1, DESFire, NTAG (ISO 14443A) | No |
| RFID key fobs | Yes: for example EM4200, T5577 | Yes | Yes |
| Adjustable and classic silicone wristbands | Yes | Yes | Yes |
| Tyvek and vinyl single-use wristbands | No | Yes | No |
| Wall access control readers | Yes | Yes: MIFARE family | Yes |
Other formats follow the same pattern: epoxy tags and PVC disc tags come in 125 kHz or 13.56 MHz, and our desktop readers read 13.56 MHz, with 125 kHz models available. For hotel locks, our lock compatibility guide lists the chips the major lock systems most often use, and MIFARE Classic vs Ultralight compares the common 13.56 MHz key card chips.
Questions buyers ask
Can a 13.56 MHz reader read a 125 kHz card?
Not unless the reader supports both frequencies. A reader built for one frequency does not power or read a chip made for the other. Dual-frequency readers exist, and dual-frequency cards, fobs and wristbands carry both chips so one credential works on both systems.
Is 13.56 MHz more secure than 125 kHz?
It can be. Most 125 kHz proximity chips send a fixed ID with no encryption. At 13.56 MHz, security depends on the chip: basic ID chips offer little protection, while chips such as MIFARE Ultralight C and DESFire add encryption. The chip matters more than the frequency alone.
