While most newer vehicles have built-in Bluetooth® for seamless smartphone streaming, older cars are limited to FM and AM radio. A Bluetooth FM transmitter uses short-range frequencies to send and receive information to Bluetooth devices via radio waves, acting as an alternative adapter. Not only does this let you stream your favorite music from your devices, but also provides hands-free calling and more.

Our review team has tested and rounded up our top picks for the best Bluetooth FM transmitters. We’ll discuss everything from readability to connectivity to help you make the right choice for your needs.

#1 Best Overall: Nulaxy KM18

Nulaxy

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Nulaxy’s car accessories are designed with the driver in mind, and the KM18 is a testament to this. Its 1.44-inch LED display is hard to miss, not to mention its flexible gooseneck allows for upward angling for even better visibility.

Thanks to its wide-ranging Bluetooth features, the KM18 can pair with almost any Apple, Android, or Galaxy device for streaming your favorite playlists or taking phone calls. And for the hard-wired electronics enthusiasts out there, the KM18’s AUX port, USB port, and micro-SD card reader offer alternatives to wireless playback.

Key Features

  • 1.44-inch LED display
  • Flexible gooseneck design
  • Noise cancellation for phone calls
  • Hi-Fi sound quality
  • Hands-free calling
  • Apple, Android, and Galaxy-compatible

Our Experience

Nulaxy Transmitter

Based on our testing, the Nulaxy KM18 is the most functional Bluetooth FM transmitter on the market. It earned the full 5 stars for its exceptional versatility, easy-to-read display, and superb connectivity.

  • Installation: The KM18 installed easily into our vehicle’s auxiliary port. We were able to establish a Bluetooth connection to our phone within seconds.
  • Streaming/Calls: Once connected, the KM18 immediately streamed our phone’s music with no interruptions. We were able to make a clear hands-free call, plus the KM18 even alerted us with the caller ID on its display.
  • Versatility: Thanks to its multiple ports, the KM18 is ready for any sort of streaming users may need. The charging rate from the USB port to our iPhone was slow, though.
Overall Rating5 out of 5
Installation5 out of 5
Streaming/Calls5 out of 5
Versatility5 out of 5

What Customers Are Saying

With an average rating of 4.6 out of 5 stars from over 100,000 reviews on Amazon, the KM18 is well-liked. Around 85 percent of all reviews left ratings of 4 stars or higher, while less than 5 percent left 1 star.

Customers who enjoy their KM18 admire its quick phone pairing even after being unplugged and placed back in their vehicles. A frequent complaint cites poor audio quality when turned up at high volumes.

What Is It Good For?

For all-around high performance, the Nulaxy KM18 is the best Bluetooth FM transmitter around. It can stream music and handle calls with no effort thanks to its strong wireless Bluetooth connectivity and it offers plenty of additional onboard options.

#2 Best For Phone Calls: Lencent T25

Lecent Transmitter

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If you’re making frequent phone calls while driving, the Lencent T25 can be a very helpful tool. This Bluetooth FM transmitter uses noise suppression technology and echo-cancellation for high-quality uninterrupted calling.

Thanks to its dual USB ports, the T25 can charge two external devices simultaneously. Its over-current protection ensures a quick charge without overloading devices, too. The T25 can also display your car battery’s voltage.

Key Features

  • Dual USB ports
  • Hands-free calling and voice navigation
  • Car battery voltage detection
  • Ambient blue light
  • Micro SD port

Our Experience

Lecent Transmitter

We scored the T25 at 4.8 stars. Its hands-free calling capabilities were unmatched by the other transmitters and we thought it was very easy to install. The T25 lost some points for lacking an auxiliary port and having a small display.

  • Installation: We had no issues installing the T25 in our testing vehicle, and the Bluetooth setup was fast.
  • Streaming/Calls: Streaming music took no hassle and the sound came through clearly. We were able to make phone calls that had no interference and didn’t echo.
  • Versatility: The dual USB ports were great for charging two devices at once. However, the T25 doesn’t have an auxiliary port, which limits the devices it can stream from a hardwire connection. It also has a very limited display that we found difficult to read.
Overall Rating4.8 out of 5
Installation5 out of 5
Streaming/Calls5 out of 5
Versatility4.5 out of 5

What Customers Are Saying

Amazon reviews for the T25 gave it an average rating of 4.4 stars. This is from over 17,000 reviews, about 70 percent of which are 5-star ratings.

Positive reviewers enjoyed the simplicity of the setup process and spoke highly of its call features. One negative reviewer claimed the T25 played back static when pushed at high volumes for extended periods.

What Is It Good For?

We recommend the Lencent T25 for those who take frequent, long-lasting phone calls. It’s a step-up from trying to use the speaker function on your phone, plus it offers efficient charging ports, too.

#3 Best Charging: Imden Bluetooth C57

Imden Transmitter

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Because of its sleek design, the Imden Bluetooth C57 has a charging efficiency of up to 80 percent to reduce power dissipation. Its over-current and over-voltage protection prevents overcharging, which can permanently damage your phone’s battery.

The C57 is equipped with intelligent temperature control as well as short circuit protection to make sure it doesn’t fizzle out after prolonged use. And its yellow-ray LED display can act as a voltmeter to measure electrical output.

Key Features

  • Built-in microphone
  • Yellow-ray LED display
  • Dual USB ports
  • Smart voice navigation
  • Multi-safety protection

Our Experience

Imden Transmitter

Because of its sensible charging and ease of use, we gave the C57 4.7 stars. It scored well for its straightforward installation but lost points due to its limited ports and decent sound quality.

  • Installation: Setting up the Imden gave us no trouble and we established a Bluetooth connection with no errors.
  • Streaming/Calls: Although music came through loud and clear, phone calls were a bit scratchy. The ‘accept call’ button on the C57 was prone to sticking, too. 
  • Versatility: Our phone gained nearly 10 percent of its battery back in less than 5 minutes when rigged to the C57. We noted the lack of ports for AUX cords and other USB sizes.
Overall Rating4.7 out of 5
Installation5 out of 5
Streaming/Calls4.5 out of 5
Versatility4.5 out of 5

What Customers Are Saying

On Amazon, around 20,000 customers rated the Imden Bluetooth C57 at 4.4 stars. Less than 10 percent of reviews were 2 stars or lower while close to 70 percent were 5-star ratings.

Among positive reviews, customers praised the C57 for its dual USB design and crisp sound. There were some negative reviewers who said their Imden device stopped pairing with their phones after being turned off.

What Is It Good For?

For drivers who frequently have multiple passengers or those who take extensive road trips, the Imden Bluetooth C57 is a practical tool. Dead electronics can take all of the joy from a car ride, but with this transmitter at your disposal, that shouldn’t be an issue.

#4 Best USB Adaptability: Anker Roav

Roav Transmitter

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While many Bluetooth FM transmitters are limited to only USB ports, the Anker Roav changes the game with its additional USB-C outlet. Considering that most smart devices are gravitating towards USB-C cords, this feature allows for greater versatility as a car charger while still providing an essential USB plug.

Another worthwhile feature of the Roav is its automatic tuning, which searches and connects to open FM radio channels. The one-button call feature combined with its high-performance microphones makes phone conversations easy with little added stress.

Key Features

  • Automatic channel scanning
  • PowerIQ 3.0 high-speed charging
  • Noise cancellation
  • One-button calling
  • Ultra-stable connection

Our Experience

ROAV Transmitter

The Roav earned 4.7 stars for having a USB-C port with fast charging capabilities. It took a while for it to find a working channel, plus disconnected without any warning. Both of these minor drawbacks were enough to deduct a small amount of points from its overall score.

  • Installation: While plugging in the Roav was simple, its automatic scanning function took a few minutes to find an open channel. Once it did, though, our phone immediately connected.
  • Streaming/Calls: The Roav streamed music and took phone calls very well. However, it lost connection at one point and had to be reconnected manually. Although it only did this once, it led our review team to question how well it would hold up in low-signal areas.
  • Versatility: We really liked the USB-C port, which charged our phone much faster than the regular USB. However, the Roav lacked an AUX port and also had no Micro SD card reader.
Overall Rating4.7 out of 5
Installation4.5 out of 5
Streaming/Calls4.5 out of 5
Versatility5 out of 5

What Customers Are Saying

Almost 8,000 customers on Amazon have reviewed the Anker Roav, awarding it an average rating of 4.4 stars. Roughly 85 percent of all reviews left a rating of 4 stars or higher. 

One of the most consistent pros that customers point out in positive reviews is that the Roav reduces static and frequency disruptions like no other transmitter. Low call quality was a frequently-cited issue.

What Is It Good For?

The Anker Roav is great for anyone who uses USB-C cords to charge their devices. It offers a faster, more reliable charge and doesn’t spare its connectivity in the process.

#5 Best Display: Sumind BT70

Sumind Transmitter

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With its 1.7-inch large LCD backlight display, the Sumind BT70 is hard to miss. It can display the song name and artist when streaming, plus a contact’s name and number when they dial in for a phone call. The BT70’s gooseneck can rotate 270.0 degrees for a more direct line of sight when adjusted appropriately.

With its multi-port design, the BT70 can play music from USB flash drives, Micro SD cards, and Bluetooth audio. Its CVC technology creates full duplex sound while also suppressing external noise for improved call performance.

Key Features

  • 1.7-inch LCD display
  • QC3.0 fast-charging port
  • Large keys
  • Compatible with Siri/Google Assistant
  • Dual USB ports
  • Micro SD port

Our Experience

Sumind Transmitter

Due to its enhanced readability and well-designed interface, we gave the BT70 4.3 stars. We liked how many extra ports it had for music streaming of all kinds. Its gooseneck design was difficult to maneuver, though, and calls did not come through as clearly as we had hoped they would.

  • Installation: The BT70 plugged in with few issues, but the gooseneck wasn’t very adjustable. It also bumped into our vehicle’s shift knob, and since the neck wouldn’t function properly we had to angle the display sideways to work. We established a Bluetooth connection in only a few seconds.
  • Streaming/Calls: Streaming came through fine, yet calls were not perfect with the BT70. Call audio was garbled in one instance, but only for a passing moment.
  • Versatility: The BT70 offers multiple charging ports and music streaming options. We thought the dual USB design came in handy for multiple passengers.
Overall Rating4.3 out of 5
Installation4 out of 5
Streaming/Calls4 out of 5
Versatility5 out of 5

What Customers Are Saying

With an average rating of 4.4 stars from close to 25,000 Amazon reviews, the Sumind BT70 has a pretty good reputation among its customers. Also, 70 percent of these reviews are 5-star ratings.

A common compliment of the BT70 is its large buttons that make navigating its display very easy. Customers also like how quickly it connects to their smart devices. Unfortunately, some customers were not happy with their BT70’s build quality, saying it fell apart after extensive use.

What Is It Good For?

We recommend the Sumind BT70 for those who may need brighter, larger displays for better readability. This Bluetooth FM transmitter is also great for road trips considering its wide range of ports.

Best Bluetooth FM Transmitters Buyers Guide

Before deciding on your next Bluetooth FM transmitter, consider what you need from your device and how it can work best for you.

What Is A Bluetooth FM Transmitter?

A Bluetooth FM Transmitter, also known as an FM radio transmitter, links mobile devices and MP3 players to a car’s stereo system using FM radio frequencies. This allows vehicles that don’t have built-in Bluetooth to wirelessly stream music and calls from a connected device. Transmitters can also charge other devices.

Some Bluetooth FM transmitters have USB charging ports, which also double as auxiliary ports. Others allow for Micro SD cards and other USB types for an even broader scope of listening options.

Our Review Standards

The best Bluetooth FM transmitters in this article went through two rounds of reviews. We started by searching Amazon for top products, looking at factors like Prime shipping eligibility, customer ratings, Amazon superlatives, and prices.

Our testing team ordered the five Bluetooth FM transmitters that best met these standards. A team member tested each product on a car, taking note of how easily the transmitters were installed in our testing vehicle, how well they streamed music and handled phone calls, and how versatile their features were. Each product was given a rating out of 5 stars based on this criteria.

Installation

This measured how easily the Bluetooth FM transmitter installed into our vehicle’s auxiliary port, also known as a cigarette lighter adapter. Once installed, we linked each transmitter to our phone. Transmitters that were installed with little hassle and linked quickly earned more points.  

Streaming/Calls

This category measured the clarity of music streaming as well as phone calls. Transmitters that streamed with little interruption scored better.

Versatility

This category measured the additional functions of each transmitter, including number of ports, extra features, and design. Transmitters with more features and intuitive design were awarded more points.

Best Bluetooth FM Transmitter Testing Process

We used a 2014 Honda Civic SE to test our Bluetooth FM transmitters. Each one was paired with an iPhone 12 Pro. At least two songs were streamed using Spotify® to test clarity. A phone call was made to another product testing team member to test the hands-free calling features as well as the clarity of each call.

FAQ: Bluetooth FM Transmitters

*Data accurate at time of publication.