FM Transmitter App for Android: What Works Instead
No app can make a phone broadcast on FM, because the phone has no transmitter inside. Bluetooth, an aux cable or a plug-in transmitter does the job.
Sending sound to a car radio over FM takes a transmitter, and a transmitter is a part, not a program. Nokia once built one into the N8 and put it on the spec sheet. We found no phone on sale today that has one, so an app has nothing to switch on. The apps that carry the name on Google Play turn out to be remote controls for a plug-in gadget, or ordinary radio players.
We read those store listings, Android’s developer reference and phone makers’ spec and support pages. Then we looked at what does get a phone’s sound into a car stereo, and at three plug-in transmitters that their makers still list.
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Can a phone be an FM transmitter?
At least one could. Nokia’s own spec page for the N8, in a copy the Internet Archive saved in 2011, lists an FM transmitter next to the phone’s FM radio.
Android has a name for the part too. Its developer reference describes a type of audio device for sending sound over FM, in the same list as wired headphones, Bluetooth and the built-in speaker. The list describes equipment that a phone may or may not have. An app can send sound to a device the phone has. It cannot create one the phone lacks.
Current spec pages mention FM only as a radio you listen to. Xiaomi’s page for the Redmi 15C lists FM radio support tied to the headphone jack, and Motorola’s and Samsung’s support pages describe an FM radio app that receives. We looked for a phone on sale whose maker lists an FM transmitter and found none.
What the apps with the name do
Search Google Play for an FM transmitter and the results fall into two groups.
Companion apps for hardware. The app called FM Transmitter says in its first line that it exists to complement the Smart Car Charger F2, a Bluetooth FM transmitter that plugs into the car. The app tunes the gadget’s frequency and pairs with it. MOJIETU, from Roidmi, connects to a Bluetooth music car charger in the same way. The App Store has an FM Transmitter app with the same description, and a Roav Charger app that says much the same about the Roav Smart Car Charger F2.
Radio players. TuneIn, Simple Radio, myTuner and many more fill the rest of the results. They play radio stations to you. None of the listings we opened claims to broadcast from the phone on its own.
So the app, where there is one, is the small half of the product. The transmitter is the thing you plug in.
Four ways that work
| Method | What the car needs | What the phone needs | What you buy |
|---|---|---|---|
| Bluetooth | A stereo with Bluetooth | Bluetooth | Nothing |
| Aux cable | An AUX socket | A headphone jack, or a USB-C to 3.5 mm adapter | A 3.5 mm cable |
| Android Auto | A compatible car or stereo | Android 9 or later and a data plan | A good USB cable, for the wired kind |
| Plug-in Bluetooth FM transmitter | An FM radio and a 12V socket | Bluetooth | The transmitter, about $20 |
Bluetooth
If the stereo has Bluetooth, use it. Put the stereo in pairing mode as its manual describes. On the phone, Google’s Android help gives the steps: swipe down from the top of the screen, touch and hold Bluetooth, tap Pair new device and choose the car from the list. The two stay paired until you unpair them.
Aux cable
A stereo with an AUX socket takes a 3.5 mm cable from the phone’s headphone jack. A phone without a jack needs a USB-C to 3.5 mm adapter first. There is no pairing and no frequency to find.
Android Auto
Android Auto puts maps, calls and music on the car’s own screen. Google says it is built into the phone, with nothing to download. The wired kind needs Android 9 or later, a data plan, a compatible car or stereo and a good USB cable. The wireless kind needs Android 11 and a phone with 5 GHz Wi-Fi. Google also says Android Auto is not available on phones that run Android (Go edition).
It is not offered everywhere. Google’s list of countries includes India, the United States, the United Kingdom and South Africa. Nigeria is not on it, and Google says most features will not work outside the listed countries.
A plug-in Bluetooth FM transmitter
This is the real FM transmitter, and the answer for a car that has a radio and nothing else. It plugs into the 12V socket, pairs with the phone over Bluetooth and rebroadcasts the sound on an FM frequency you choose. You tune the car radio to that frequency.
Three plug-in FM transmitters
We kept to makers whose own websites list the product today.
Nulaxy KM18. Nulaxy’s site describes a 1.44-inch screen on a bendable neck that shows the FM frequency, incoming calls, the music playing and the car’s battery voltage. It plays from Bluetooth, a microSD card or an aux cable, handles hands-free calls and fits 12V and 24V sockets. Nulaxy prices it under $20 on its own site. Find the Nulaxy KM18 on Amazon.
Scosche BTFreq Pro. Scosche lists a digital display, hands-free calling, and two charging ports, one USB-C and one USB-A, at 12W each. It also has an audio jack that can feed a stereo’s AUX socket directly, with a cable you supply. That makes it useful in a car with AUX but no Bluetooth, where the wire avoids FM altogether. It is about $20 on Scosche’s site. Find the Scosche BTFreq Pro on Amazon.
Syncwire 48W Bluetooth FM transmitter. Syncwire’s page gives it two charging ports, a 36W USB-C and a 12W USB-A, with noise suppression for calls and a 36-month warranty. Pick it if the phone charger matters as much as the music. It is about $25 on Syncwire’s site. Find the Syncwire Bluetooth FM Transmitter 48W on Amazon.
The Roav Charger app mentioned earlier was made for the Roav SmartCharge range from Anker. Roav’s own website now shows that range with no products in it, so we left it out.
Setting one up
Nulaxy’s support page gives the routine for the KM18:
- Plug the transmitter into the 12V socket and start the car.
- Turn the car radio to a frequency with no station on it, only static.
- Set the transmitter to the same frequency.
- Open Bluetooth settings on the phone, pair with the transmitter and press play.
If you hear hiss, Nulaxy’s advice is to hunt for a frequency that is completely empty, then turn the phone and the transmitter up and the car radio down. It also warns that some cars keep the socket live with the engine off, so unplug the transmitter to spare the battery. Only one phone can be connected at a time.
Do not expect range. In the United States, the FCC says unlicensed FM devices of this kind are limited to an effective range of about 200 feet, or 61 metres. They are weak on purpose, which is why a real station on the same frequency will win.
Which to pick
- The stereo has Bluetooth: pair the phone and buy nothing.
- The stereo has AUX but no Bluetooth: a 3.5 mm cable. A wire has no station to clash with.
- The car supports Android Auto and you live in a listed country: use it, for the maps as much as the music.
- The car has an FM radio and nothing else: a plug-in transmitter. The Nulaxy KM18 for the screen and the microSD slot, the Scosche BTFreq Pro if you may move it to a car with AUX.
What happened to the old list
The 2019 version of this article listed ten apps, among them Simple Radio, myTuner Radio, iHeartRadio and SiriusXM. They are apps for listening to radio stations, and none of them could ever send sound to a car stereo. The ones still worth installing are in our guide to radio apps for Android, which also explains the FM receiver that some phones do have.
Quick answers
Is there an FM transmitter app for Android?
Not one that works alone. The app named FM Transmitter on Google Play is a controller for a plug-in Bluetooth FM transmitter, and says so in its listing.
Can I use my phone as an FM transmitter without hardware?
No. Broadcasting on FM needs a transmitter in the phone, and we found no current phone whose maker lists one.
Is there an FM transmitter app for iPhone?
The App Store apps with the name are the same two kinds: companions for a plug-in transmitter, and radio players.
How do I play music from my phone to a car radio without Bluetooth or aux?
With a plug-in Bluetooth FM transmitter in the 12V socket. The phone connects to it over Bluetooth, and the car radio picks it up on an empty FM frequency.
Does a Bluetooth FM transmitter need an app?
Not usually. Nulaxy’s instructions have you pair from the phone’s Bluetooth settings, and none of the three product pages above asks for an app.
