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A versatile, no-nonsense Bluetooth transmitter.

A Bluetooth transmitter for high-quality calls.

A Bluetooth transmitter with a USB-C port.

A Bluetooth transmitter with a bright display.

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.

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 .

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.

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.

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.

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 .

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.

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.

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.

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.

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 .

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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

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.

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.

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.  

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

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.

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.

You’ll want to match your transmitter’s frequency to that of the desired station on your radio for streaming. Most manufacturers provide a range of available FM frequencies that can be used for pairing. Be sure to choose a clear frequency, as ones in use will not work with a transmitter.

If you leave a Bluetooth FM transmitter on when your car isn’t running, then yes, it can drain your battery. Always check that your transmitter is turned off before leaving your vehicle.

As long as your vehicle has an FM radio connection and an auxiliary port, it can be used to establish a Bluetooth connection . Make sure you turn your transmitter off when not in use, as some vehicles won’t automatically deactivate them.

Some models may allow for AUX cable playback while others don’t, so checking your model’s features before purchasing is important.

*Data accurate at time of publication.

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