If you want to use a pair of wired headphones with a phone or other source that lacks a headphone jack, a Bluetooth headphone adapter is the simplest option.

This type of Bluetooth audio receiver is battery powered and generally the size of a USB stick (or smaller), and you plug your headphones into it. The adapter receives a Bluetooth audio signal from your phone, lets you control playback, and has a microphone for you to take calls or do video chats—so you can keep your phone or tablet stashed safely in a pocket or bag or charging across the room. You still have to deal with the headphone cable, but it’s not connected directly to your source.

These small adapters are also a good choice for use in a car, to stream audio from your mobile device to an older car stereo that lacks Bluetooth. But your car’s stereo system must have an auxiliary audio (3.5 mm) input for this setup to work.

Top pick: 1Mii MiiLink ML100

Photo: Michael Hession

Top pick

This adapter provides a stable wireless connection and offers good battery life and a decent microphone. Unlike similarly priced competitors, it has no major flaws.

1Mii’s MiiLink ML100 is our favorite Bluetooth headphone adapter for most people because it does what it’s supposed to do without any glaring issues or quirks—and we can’t say the same about the other adapters in its price range that we tested.

The Bluetooth performance is reliable. The ML100 paired easily with our devices, and every time we powered it back on, it automatically reconnected to the last paired device.

It was also one of the most consistent performers in Bluetooth range and reliability, exhibiting fewer pops and signal dropouts as we moved around the house.

The design is compact and user friendly. While the ML100 is similar in form to most of the other low-priced headphone adapters we tested, it has a few distinguishing design elements that made it easier to use.

This adapter is roughly the size of a domino and relies on USB-C for charging. A large multifunction button sits alone on the front panel. That button controls Bluetooth pairing/connection, play/pause, and call answer, and it’s easy to find by feel since there are no other buttons around it. There’s also a slowly pulsing blue light around the button that improves visibility without being too distracting.

The ML100 has a dedicated power on/off switch, which is surprisingly rare. With many adapters, you have to press and hold the multifunction button to wake up the adapter; inevitably you end up holding it too long and putting the device in Bluetooth pairing mode when you don’t mean to. And when you press the multifunction button to try to disconnect, you may be unsuccessful and not know that your phone is still connected. A dedicated power button is just clearer.

A set of + and - buttons on the side lets you control volume up/down with a quick press and track forward/reverse with a long press. The ML100 takes over the volume control of your source, or at least it did so with our iPhone XR and MacBook’s iTunes.

The built-in microphone sounds better than those of the competition. The ML100’s microphone offered the best vocal clarity among the sub-$35 adapters we tested, though the volume was a bit lower than we would’ve preferred. Some models we tested had ridiculously low volume levels, while others sounded harsh, muffled, or unnatural, or picked up more hiss and background noise.

That said, the ML100’s mic didn’t sound great—voices definitely weren’t as clear and natural as what you’ll get if you move up to our upgrade pick. In that model’s price range, all of the adapters had much better-sounding microphones. But the ML100’s mic performance was adequate for short phone calls and video chats.

Battery life and power output are solid. The ML100’s stated battery life is 14 hours, and we got about 13 hours in our test.

As for the power output to drive the attached headphones, the ML100 measured 27.7 milliwatts into 32 ohms. Although that’s much lower than what you can get from our upgrade pick, the ML100 should be fine to power basic earphones and headphones that aren’t especially hard to drive. I got plenty of volume from my Etymotic earbuds and Bowers & Wilkins headphones.

Flaws include limited customization options and Bluetooth codec support. This is a connect-it-and-forget-it device, with no accompanying mobile app to customize how the buttons work or to get feedback on other details such as battery life and Bluetooth format. Many people may appreciate that simplicity, but if you’re the type who wants more control over the user experience, you’ll need to move up in price to our upgrade pick.

This adapter supports only the standard SBC codec, not higher-performance options like LDAC, aptX HD, or aptX Low Latency. This was true of almost all the low-priced adapters we tested; again, you’ll need to move up in price to get more codec support.

You may not need that support, though, depending on which codecs your phone supports. (You can read more about Bluetooth codecs in this article.) I did not observe any significant latency issues with the ML100 when watching YouTube videos on my iPhone.

Upgrade pick: Qudelix-5K

Photo: Michael Hession

Upgrade pick

This adapter has more features, more power, and a better microphone than our top pick. But the higher price may be worth it for only the serious audio fan.

The Qudelix-5K is a worthwhile upgrade for those who own harder-to-drive headphones or want to have more control over their listening experience. But for the more casual listener who just wants a simple, affordable Bluetooth headphone adapter, this one is probably overkill.

This adapter has a ton of customization options. Unlike all of the cheaper adapters we tested that offer little to no feedback or customization, the Qudelix-5K works with a mobile app for iOS and Android that’s loaded with tools for audio enthusiasts—all in a clean, clear presentation.

Among the options are the ability to get precise feedback on battery life and Bluetooth codec, change the behavior of buttons, prioritize the power output based on sound quality or battery life, and adjust the audio quality with a 10-band equalizer. A lot of the advanced controls require some understanding of audio principles.

The Qudelix-5K has more amp power and a better microphone. If you own a pair of higher-end audiophile headphones with a low sensitivity rating (below 98 decibels) or a high impedance (above 100 ohms), you may need more amp power than a cheap adapter delivers to produce satisfying volume levels. You can read more about this in our guide to portable headphone amplifiers.

We measured 80 mW into 32 ohms from the Qudelix-5K’s standard, unbalanced headphone output, and 254 mW from the balanced output. That is more than enough power to drive almost every headphone type on the market.

All of the pricier adapters we tested (above $70) had notably better built-in microphones than what we heard from cheaper adapters. Whereas the ML100’s mic delivered passable vocal quality for the occasional phone call, the Qudelix-5K’s mic produced excellent vocal clarity and minimal background noise (though we did not test it in wind).

If you use wired headphones that already have an inline remote/mic, the Qudelix app gives you the option to keep using your headphone mic if desired.

This adapter has a simple, compact design. The Qudelix-5K is small and light, with a USB-C charging port and a helpful clip on the back to easily connect it to your clothing or bag. It has dedicated volume controls on one side; on the other side are power and play/pair buttons that also handle track skip.

While the buttons aren’t labeled on the adapter itself, the cardboard package it comes in has diagrams to show you what every button and port does. Once you get a feel for where everything is located, the buttons are pretty easy to find and use without looking—more so than on competing models that lined up all the buttons on one side.

The USB-C port also functions as a USB DAC, supporting audio sample rates up to 24 bits/96 kHz. You can read more about the DAC element in our guide to portable headphone amps with built-in DAC.

Bluetooth performance was excellent. The Qudelix-5K provided the most reliable Bluetooth connection in its price class, and we encountered no problems during the pairing process. Plus, this model supports most of the major codecs, including AAC, aptX HD and Adaptive, and LDAC.

The only codec missing was aptX Low Latency, which can help sync up the audio and video when you’re watching a source like YouTube. But the included aptX Adaptive codec does help reduce latency, too, if your phone supports it.

As for battery life, we got up to 15.25 hours in the standard power mode, which was the best in our most recent round of testing. In the high-performance mode, we got a still-good 11.5 hours.

The Qudelix-5K does not take over the volume control of your source, so you’ll want to make sure the volume is set high enough on your source device before you start using the Qudelix’s volume controls.