How to merge several audio files or MP3s into one

A lecture recorded in several parts, voice messages to put together, a podcast made of an intro, an interview and an outro, a playlist of songs for a party or a slideshow, an audiobook split into dozens of tracks: merging audio files gives you a single file that is easier to listen to, share and archive.

This guide explains how to join several MP3s (or WAV, M4A, FLAC…) online, how to set the order, trim each file before joining, and add silence or a fade between tracks.

Merge audio files, step by step

1. Open Merge audio.
2. Drop at least two files: MP3, WAV, M4A, AAC, OGG or FLAC. You can mix formats.
3. Set the order with the Move up and Move down buttons.
4. If needed, set the start and end of each file to remove silence or an unwanted passage.
5. Choose a silence between files, and fades if you like.
6. Choose the format (MP3 or WAV) and click Create the audio file.

The result downloads as merged-audio.mp3 (or .wav). The total duration updates live while you adjust the settings.

Trim each file before merging

This is what simple merge tools often lack: recordings rarely start at exactly the right moment. Here, each file has its own waveform and its own start and end times, so in a single pass you can:

• remove the few seconds of silence at the start of each voice message;
• keep only the useful part of each recording;
• shorten an intro that runs too long.

For finer edits on a single file, such as removing a passage in the middle, use Trim audio first.

Silence and fades between tracks

• Silence between files: from 0 to 10 seconds, in half-second steps. One or two seconds is enough to clearly separate the parts of a lecture or voice messages. Leave it at 0 for a continuous flow.
• Fade in and fade out: applied to each file, up to 10 seconds. They avoid abrupt starts and endings, especially between two songs.

Even without fades, a very short transition is applied at each join to avoid audible "clicks".

Which quality should you choose?

The merged file can be exported:

• as MP3, at three levels: Standard (128 kbit/s) for voice, High (192 kbit/s) for podcasts or music on headphones, Maximum (320 kbit/s) for music. The estimated size is shown for each level;
• as WAV, uncompressed, if you will keep editing the file in an audio editor. It is about ten times larger than an MP3.

Audio is rendered at 44.1 kHz, in stereo if at least one of the files is stereo. Files from different sources (phone, recorder, downloaded track) are therefore combined into one consistent format.

Limits to know

• Up to 20 files and 100 MB in total per merge.
• The tool is free up to 5 files a day across all free tools, and each file added to the merge counts. A subscription removes this limit if you need to join more files.
• Merging runs in your browser. On an older phone, joining an hour of audio can take a while.

Your files stay on your device

As with trimming, merging happens right in your browser: your recordings are not sent to our servers to be processed. A good point for private voice messages, interviews or meeting recordings.

Common uses

Situation	Suggested settings
Join the parts of a lecture	1 to 2 s silence, MP3 Standard
Combine voice messages	Start of each file adjusted, 1 s silence, MP3 Standard
Assemble a podcast episode (intro + interview + outro)	1 s fades, MP3 High
Music compilation	2 to 3 s fades, MP3 Maximum
File meant for further editing	WAV

Frequently asked questions

How do I merge MP3 files for free?

Open Merge audio, drop your MP3s, set the order and export. It is free up to 5 files a day.

Can I merge different formats, such as an M4A and an MP3?

Yes. All files are decoded, then combined into a single MP3 or WAV file.

How do I change the order of the files?

With the Move up and Move down buttons next to each file. The number in front of the name shows its position in the final file.

Are my files uploaded to a server?

No, merging happens in your browser and your files are not sent anywhere to be processed.

Can I merge video files?

This tool handles audio only. To get the sound out of a video, convert it first with MP4 to MP3, then merge the resulting files.