Batch convert to MP3: drop a folder, get one ZIP back
To batch convert a folder to MP3, drop the whole folder onto mp3fy. It walks every subfolder, queues each audio and video file it finds, converts several in parallel, and hands everything back as a single ZIP. The work happens on your device (nothing is uploaded), and there is no cap on file count or total size.
One file is never the problem. The folder is: a semester of recorded lectures, ten years of voice memos, a rehearsal archive scattered across five formats. Converting those one at a time through an upload site is an afternoon gone. Here is the whole workflow in four steps.
The four-step workflow
- Set the bitrate first. The options row applies to files added next and to anything still waiting in the queue, so pick a target before the drop and the entire batch inherits it. Spoken word is comfortable at 96–128 kbps; music usually deserves 192 kbps or better. Which MP3 bitrate has the numbers if you’re unsure.
- Add the folder. Press the Add folder tile, or drag the folder straight onto the page. mp3fy walks the entire tree, subfolders included, and queues everything it recognises: an MP4 lecture capture next to a stack of FLAC rips next to a pile of phone recordings.
- Watch the queue drain. Every file gets its own row with live numbers: percent done, conversion speed, time remaining, projected output size. The figures are measured, not animated. When a file is slow, the speed column tells you. Several files convert at once, and the parallelism scales with your CPU cores, so an eight-core laptop genuinely works eight times as wide as the queue allows.
- Download all as ZIP. When the batch finishes, one button packs every MP3 into a single archive. You can still save any file individually if you only need a few of them.
Practical tips
- Mixed formats are fine. Audio and video share one queue, and every file comes out as an MP3 with the same settings, whatever it went in as.
- Set options before dropping. Files that are already converting keep the settings they started with; only files added next, and those still waiting, pick up a change.
- Extra tabs don’t compete. Every mp3fy tab shares one queue, and converting carries on as long as any one of them stays open, so you can browse the site without pausing the batch.
- Undecodable files don’t block anything. If the browser can’t decode a stray file (an old WMA, say), that row simply gets a one-press cloud button while the rest of the batch sails through on-device.
- Closing the results isn’t fatal. Finished files stay in History for seven days, so you can re-download without reconverting. They never left your machine to begin with. See how on-device conversion works.
Built for multi-gigabyte batches
There is no total-size ceiling, because there is nothing to upload and no server quota to exhaust. That’s deliberate. The ZIP is generated on your device and streamed straight into the download as each entry is written, so a 40 GB batch of concert footage never needs to fit in memory, and neither does the archive. Queue the folder, leave a tab open, and collect one file at the end.