What is the frequency of a key fob signal?

The short answer is that key fob signals operate in radio frequency bands that vary by region and technology. In North America, many remotes use around 315 MHz; in Europe, 433.92 MHz is common, with some models also using 868 MHz or 915 MHz for newer systems. The immobilizer component inside the key relies on a separate, low-frequency field (typically around 125 kHz) to wake and authenticate the chip. Overall, the exact frequency depends on the country, vehicle model, and whether you’re using a traditional fob or a smartphone-based key.

Common frequencies by region

Before listing typical bands, it’s important to understand that regional regulations and vehicle designs drive which frequencies are used. The most widely seen bands are summarized below.

• 315 MHz: Widely used for remote keyless entry in North America (United States and Canada).


• 433.92 MHz: Standard in many European markets and several parts of Asia for remote unlocking and entry systems.


• 868 MHz and 915 MHz: Used by some newer European and global models, offering higher data capability and sometimes longer range.


• 125 kHz (low-frequency, LF): Used for the immobilizer/transponder wake-up, a separate channel from the remote unlock signal.

These variations explain why there isn’t a single universal frequency for key fobs. Some brands also deploy multiple bands within the same system to support different regions or features. Additionally, smartphones and “smart key” systems increasingly rely on Bluetooth at 2.4 GHz to supplement or replace traditional fob signaling in proximate scenarios.

Regional snapshots

In practice, North American vehicles commonly rely on 315 MHz remotes, while many European models use 433.92 MHz. Some high-end or newer vehicles may incorporate 868 MHz or 915 MHz bands for enhanced capability. The immobilizer component uses a low-frequency wake-up signal (around 125 kHz) regardless of the remote band.

Immobilizer vs remote communication frequencies

The key system typically operates on two distinct RF domains: one to wake and authenticate the embedded transponder (immobilizer) and another to perform the actual remote locking/unlocking or starting actions.

• Low-frequency wake-up: Approximately 125 kHz, powering the passive transponder in the key to allow authentication by the car's immobilizer system.


• High-frequency remote signal: The actual unlock/start commands are transmitted in the RF band appropriate for the region (315 MHz, 433.92 MHz, 868/915 MHz, etc.).

Understanding these two channels clarifies why a single “frequency” label doesn’t capture the full operation of key fob systems. In addition, many vehicles now pair these traditional signals with smartphone keys that use different tech, such as Bluetooth, to confirm proximity before unlocking.

The rise of smartphone keys and the role of 2.4 GHz

As automakers expand digital access, smartphone-based keys are becoming more common. These systems typically rely on Bluetooth Low Energy (BLE) at 2.4 GHz to exchange cryptographic tokens with the vehicle, providing proximity-based unlock and start features. This does not replace the traditional fob’s remote RF signaling in many cars, but it does shift how proximity and authorization are handled in modern designs.

• Bluetooth Low Energy (2.4 GHz): Used by many smartphone key implementations for proximity verification and access control.


• Traditional fob signals: Continue to operate in established RF bands (315/433/868/915 MHz) to support doors, trunk, and engine start in regions where those systems are deployed.

Automakers are balancing backward compatibility with legacy remotes and new smartphone-based access, often maintaining multiple communication channels for reliability and regional compliance.

Security and privacy considerations

Frequency alone does not determine security. Modern key fob systems rely on rolling codes, cryptographic handshakes, and sometimes frequency-hopping or proximity-based authentication to deter interception or replay attacks. Regulations and standards in different regions influence how these security features are implemented, and manufacturers continually update systems to counter evolving threats.

Owners should keep remotes away from high-interference areas and be mindful of where a vehicle is parked, since signals can potentially be captured in transit. Regular software updates from manufacturers help ensure keyless-entry protocols stay current against emerging security concerns.

Summary

Key fob signaling does not use a single universal frequency. The most common bands are 315 MHz in North America and 433.92 MHz in Europe, with some systems also using 868 MHz or 915 MHz. A separate low-frequency channel around 125 kHz powers the immobilizer transponder, while newer smartphone-based keys may use Bluetooth at 2.4 GHz for proximity-based access. Regional regulations, vehicle design, and security measures shape how these signals are deployed and protected.

What signals do key fobs emit?

A key fob communicates with a receiver or a central system, most commonly a vehicle's or a building's access control system, using radio frequency identification (RFID) and rolling code technology. The fob sends a unique, encrypted signal to the receiver, which then authenticates the code to perform an action, such as unlocking doors or starting a car. 
Key functions and technology

• RFID technology: Key fobs use RFID to store and transmit a unique identifier, similar to an electronic barcode. This allows the receiver to identify the fob. 
• Radio frequency: The fob sends radio signals to a receiver in the car or door lock. This signal contains a unique, encrypted code. 
• Rolling code technology: To prevent signal interception, the code changes every time the fob is used. This makes it very difficult for a hacker to duplicate the signal. 
• Receiver and antennas: The vehicle's or building's system has a receiver to detect the signal. In a car, multiple antennas are used to determine the location of the key fob, ensuring it is inside or near the vehicle for certain functions like passive entry. 
• Multi-factor authentication: Some advanced key fobs can also be used as part of a multi-factor authentication process, often incorporating biometric data like a fingerprint, to provide an extra layer of security. 

How far away can a key fob be cloned?

Some RFID copiers can capture signals through walls and windows, making key fobs vulnerable even inside homes. How far away can a car key be cloned? In some cases, it can be over 100 meters using advanced relay boosters. Without the right security precautions, your key signal is at risk even when stored indoors.

Is there a way to locate a key fob?

Yes, you can locate a key fob by using a Bluetooth tracker attached to it, checking common spots and retracing your steps, or using a spare key to trigger a sound from the fob. Bluetooth trackers use a smartphone app to ring the fob when close or a network of other users to pinpoint its location when far away. 
This video explains how to find your key fob by using the car's features: 59sNorthStead LandscapingYouTube · Dec 29, 2022
Using a tracker

• Attach a Bluetooth tracker: Add a tracker like a Tile, Apple AirTag, or Chipolo to your key fob. 
• Use the app: Open the corresponding app on your smartphone to see the location on a map or make the fob ring if it's within Bluetooth range. 
• Use a community find network: If the fob is out of range, the app can anonymously use other nearby users' devices to help locate your fob's last known position. 
• Use the "Find My" network: If you have an Apple AirTag, you can use the "Find My" app on your iPhone, iPad, or Mac to locate the fob. 

Without a tracker

• Retrace your steps: Mentally or physically retrace your steps to where you last had the key fob. 
• Check common hiding spots: Look in places like under couch cushions, in pockets, on countertops, or in bags. 
• Use a spare key: If your vehicle has a feature that makes the fob beep or flash a light, use a spare key to trigger that function and listen or look for the sound/light. 
• Check the vehicle: If you think the fob is inside your car, check between and under the seats, in the console, or in door pockets. 
• Replace the battery: A weak battery can reduce the fob's signal range. Replacing it might help, especially if you're trying to use a remote feature on the car. 

What frequencies do key fobs use?

Key fob frequencies vary by region but commonly operate at 315 MHz in North America and Japan, and at 433.92 MHz in Europe, Asia, and Japan. Some European systems may also use the 868 MHz band. The frequency is a radio wave used to transmit a coded signal from the fob to the car. 
This video demonstrates how to use a Flipper Zero to scan for key fob frequencies: 40snikkolausYouTube · Jun 1, 2022
Common key fob frequencies

• 315 MHz: Widely used in North America and Japan.
• 433.92 MHz: Common in Europe, Asia, and Japan.
• 868 MHz: Also used in Europe to accommodate more devices. 

Other frequencies

• 125 kHz and 13.56 MHz: These are lower frequencies sometimes used for passive RFID tags for features like keyless entry and start systems.
• 135 kHz: Used for a low-frequency "wake-up" signal that the car emits to prompt the fob to respond with its VHF signal. 

How to identify your fob's frequency

• Check the fob: Some fobs may have the frequency printed on the casing or a sticker. 
• Consult the vehicle's manual: The owner's manual should list the specifications for your car's keyless entry system. 
• Use a frequency tester: Specialized tools are available to test and identify the frequency of a key fob.