How to convert FLAC to MP3 on a Mac, offline
By Himanshu Ranjan · Updated 8 November 2026
Select your FLAC files in Finder, open FileDial, and run Convert › Convert to MP3. You get a new MP3 beside each FLAC, the lossless original stays untouched, and nothing is uploaded. Going from FLAC to MP3 is a one-way trip to a smaller lossy file, so keep the FLAC masters.
What changes when FLAC becomes MP3
FLAC is lossless: it decompresses to an identical copy of the original audio. MP3 is lossy, so it discards detail that listening models suggest most people will not miss, in exchange for a much smaller file. You cannot get the lost detail back by converting the MP3 to FLAC later.
So treat the FLAC as the master and the MP3 as a copy for phones, cars and players that do not read FLAC. macOS itself plays FLAC, but plenty of hardware does not.
Convert FLAC to MP3 with FileDial
The workflow is the same whether you have one track or a whole album folder.
- In Finder, select the .flac files. Command-A selects everything in an open album folder.
- Hold the right Option key to open the dial.
- Pick Convert › Convert to MP3 and release.
- The new .mp3 files appear beside the FLAC files. Use Undo on the result card if you want them removed.
Keep tags and cover art in mind
FLAC stores text tags such as title and artist as Vorbis comments and can carry cover art. After converting, check the MP3 in your player. If a track is missing its artwork, Combine › Add cover art takes a track and a picture and makes a new copy without re-encoding the sound. Tags › Edit tags… fixes titles and artists, and empty fields keep what is already there. Tags › Extract cover art saves the embedded picture as an image file.
Alternatives already on your Mac
The Music app is the built-in route, but it is built around library songs and its listed conversion targets are AIFF, WAV, MP3 and AAC. If you only want to listen to FLAC on a Mac or iPhone you may not need to convert at all, because macOS and iOS have supported FLAC since High Sierra and iOS 11. Convert only when the destination refuses FLAC.
Lossless is not the same as large
FLAC compresses audio without discarding anything, which usually makes the file noticeably smaller than uncompressed WAV or AIFF. Wikipedia cites figures that vary, with one passage saying roughly 50 to 70 percent of the original size, so treat any exact number with caution. MP3 is smaller again because it throws information away, with a typical 128 kbit/s MP3 around an eleventh of CD audio size by the same source.
That gap is why people carry MP3 copies: a library that fills a drive in FLAC fits comfortably in MP3. The sensible habit is a two-folder system, FLAC masters on a big drive and MP3 copies for devices.
Choosing between MP3 and other lossy options
If your devices are Apple devices, an M4A copy made with Convert › Convert to M4A is another reasonable lossy target, and AAC generally sounds better than MP3 at the same bit rate. If you need the broadest support, including old players and car stereos, MP3 is the choice. Convert › Convert to Apple Lossless keeps the sound intact while remaining friendly to Apple software, which suits you if FLAC is the problem rather than size.
Check results before deleting anything
After a batch, spot check a few files: play the start, a loud passage and the end. Sort the folder by size to catch anything that came out suspiciously small. Only after that think about archiving the FLACs. Batch › Checksums (SHA-256) writes a text file of checksums if you want proof that a backup copy of your masters matches, and Archive › Make ZIP packs a folder if you need to move it.
A built-in Finder option, and where it falls short
macOS has a Finder Quick Action called Encode Selected Audio Files. Select your tracks, right-click, and look under Quick Actions (on some setups under Services) for it. It encodes to M4A at a quality or bitrate you pick, rather than to MP3, so it suits Apple-only listening and not a car stereo that wants MP3. If MP3 is the requirement, it cannot help, and you need a converter that writes MP3 such as FileDial's Convert › Convert to MP3.
In Terminal, afconvert may read FLAC on current macOS and write formats such as M4A or WAV, but it has no MP3 encoder, so it is a stepping stone at best.
Common mistakes to avoid
The first mistake is deleting the FLAC files after converting, then discovering the MP3 sounds worse on better speakers. Keep the masters. The second is converting an MP3 or other lossy file into FLAC to make it look high quality, which only produces a large file with the same sound. The third is converting an entire library without testing one album. Convert one album, play it on the device it is for, and only then do the rest.
Also watch the folder structure. FileDial saves each result beside its source, so a folder of FLAC files ends up with MP3 files mixed in. Sort them apart with Batch › Sort into folders by type, which makes sorted copies in a new folder, or move the MP3s with Share › Move to… so they are ready to copy to a device.
Why do it offline
Music libraries are large, and uploading gigabytes to a web converter is slow and exposes your files to a third party. In FileDial the conversion never leaves your Mac. FileDial runs every tool on your Mac and never uploads a file, and all tools work with Wi-Fi off.
Questions
Is FLAC better than MP3?
FLAC preserves the audio exactly, while MP3 trades some detail for a much smaller file. Whether you can hear the difference depends on your gear, your ears and the MP3 bitrate. For archiving, FLAC is the safer choice. For sharing or tiny storage, MP3 is practical. The usual advice is to keep FLAC for archives and use MP3 for phones, cars and sharing, since the right choice depends on where the file will be played.
Can I convert FLAC to MP3 and back without loss?
No. Once the audio is MP3, the discarded detail is gone. Converting that MP3 back to FLAC makes a larger file with the same lossy sound. Always keep your FLAC originals, which FileDial does by saving a new copy. Think of it as a one-way door: the FLAC can always make a new MP3 later, but a deleted FLAC cannot be rebuilt from an MP3.
Will my album art survive conversion?
It depends on the player, so check after converting. FileDial has Combine › Add cover art to attach a picture to a track as a new copy, and Tags › Extract cover art to save the picture from a file. If the artwork is missing, attach the picture again to the MP3 and check how your player displays it, since players handle embedded art differently.
Do I need to install anything extra to convert FLAC on a Mac?
Not with FileDial. Convert › Convert to MP3 handles FLAC input directly from Finder, offline. You will need macOS 14 or later on an Apple silicon Mac to run the app. macOS has played FLAC natively since High Sierra, so you only need the converter when a device or website will not accept FLAC.