Tool 13 · Audio joiner · Free · No signup
Audio joiner and merger.
Merge or combine audio files into one: drop two or more, put them in order and choose what happens between them: nothing, a silence gap or a crossfade. Listen to the result, then download one MP3 or WAV. It all runs in your browser.
01 Files, in order
MP3, WAV, M4A, AAC, FLAC, OGG and Opus, mixed freely; drag a row or use the arrows to reorder. The files are read on your device and never upload.
02 Between files
Each file starts the moment the last one ends, sample for sample: no click, no added silence.
03 Download
About 1 KB. 192 kbps is transparent for most music; 320 if it is going back into an editor. One file: audio-joined.mp3.
One file, then a video
A joined file is usually on its way somewhere: a mix to YouTube, a podcast with its intro to Spotify, chapters to an audiobook app. Above, the joined track in the Neon style of our waveform video maker. Drop the download on MP3 to MP4 for a cover and the sound, or on the music visualizer for something that moves.
How to join audio files
Most online joiners upload your files, join them on a server and make you wait for a download link. This one decodes each file in the browser, lays the audio end to end at 44.1 kHz with the gap or crossfade you chose, and encodes the result once, on your device. The crossfade uses an equal-power curve, the one mixing desks use, so the level holds steady through the overlap instead of dipping in the middle.
- Drop all the files on the page at once, or click to choose them. MP3, WAV, M4A, FLAC and OGG can be mixed.
- Put them in order: drag a row, or use the arrows on a phone. Remove any you do not want with the cross.
- Choose what goes between them: back to back, a gap of silence, or a crossfade, and set the seconds.
- Press Play and click the timeline to check each join.
- Pick MP3 or WAV and press Join and download. The file is named after the first one, with -joined on the end.
Related
- MP3 to MP4The joined file with a cover as a 1080p video, ready for YouTube.
- Music visualizerA mix or a playlist as a video that moves with the beat.
- Waveform video makerFor joined podcast segments: a waveform that follows the voice.
- MP3 tag editorGive the joined MP3 a title, an artist and a cover.
- BPM and key finderCheck the tempos before you crossfade two songs.
- Audio looperOne part of a file repeated, or stretched to fill an hour.
- Audio trimmerCut each file to the part you want before you join them.
- Audio splitterThe opposite: one long file cut into many parts.
- All guidesHow-tos and comparisons from the people who build the tools.
Questions
Can I join files of different formats?+
Yes. Each file is decoded to plain audio first, so an MP3 voice memo, a WAV from a recorder and an M4A from an iPhone can sit in the same list. Everything is brought to 44.1 kHz on the way in, and if any file is stereo the mono ones are played on both channels, so the joined file has one consistent format from start to end.
Why does it re-encode instead of just sticking the MP3s together?+
Gluing MP3 files byte to byte only works when every file has the same sample rate, channel count and encoder settings, and even then players can show the wrong length and click at the joins, because each file carries its own header and encoder delay. Decoding, joining and encoding once gives one clean file with a correct length and seamless joins. At 192 kbps or more, one extra MP3 generation is not something you can hear; pick WAV if the result is going back into an editor.
Gap or crossfade: which should I use?+
Back to back is right for parts of one recording that were split, like chapters of an audiobook or takes recorded in pieces. A gap of one or two seconds suits separate tracks played in a row, the way an album or a playlist feels. A crossfade of three to six seconds suits a DJ style mix or a compilation of songs at similar tempos; for speech it usually sounds wrong, because two voices overlap.
How long can the joined file be?+
There is no limit we set, and no time limit on the free version. The ceiling is your device's memory: the audio is held uncompressed while you work, about 20 MB a minute in stereo, so an hour of audio needs over a gigabyte. A laptop handles a couple of hours; on a phone, keep it to about half an hour. Encoding an MP3 runs at many times real speed and shows its progress.
Which formats can I drop?+
Anything your browser can play: MP3, WAV, M4A and AAC, FLAC, OGG Vorbis and Opus in current Chrome, Edge and Firefox. If a row says the browser cannot decode a file, that codec is not built into your browser (in Chrome the usual ones are WMA, AIFF and Apple Lossless); convert that one file first or try another browser.
Is anything uploaded?+
No. The files are read, decoded, joined and encoded on your device, and the download is made there too. Nothing about the files is sent anywhere; the page only counts that a join was saved, with the format and the number of files, never a name or the audio.
Can it mix two files so they play at the same time?+
No. Merging here means end to end: the second file starts where the first one stops, or overlaps it only for the crossfade. Playing a voice over a music bed, or two songs on top of each other for the whole length, is mixing, a different job that needs a level for each track on a timeline. A free multitrack editor such as Audacity does that: import both files, each lands on its own track, set the levels and export.
Can I turn the joined audio into a video?+
Yes, that is what the button under the download is for. Drop the joined MP3 on our MP3 to MP4 page for a still cover with the sound, ready for YouTube, or on the music visualizer for a video that moves with it. A long mix with a single cover is the usual way to post a playlist or a DJ set to YouTube.