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Audio Joiner
This audio joiner puts your recordings and songs together into one file: in the order you choose, each cut to the part you want, back to back, with a gap or with a crossfade. It measures every part and brings them all to one loudness, so a quiet recording no longer sits next to a loud one. It runs in your browser, so you can merge audio files without uploading them.
Three recordings, one level
Recorded at different levels, joined with 0.8 seconds between them and matched to −16 LUFS.
- Part 1 −29.0 LUFS, +13.0 dB
- Part 2 −20.0 LUFS, +4.0 dB
- Part 3 −25.0 LUFS, +9.0 dB
The parts as they went in
Made from this site’s own tracks and recordings by the joiner in the studio.
- no sign-up, no file limit
- Free
- every part matched to −16 or −14 LUFS
- One level
- crossfades, or up to 5 s of silence
- Up to 10 s
- to the millisecond, before joining
- Cut each part
- MP3, M4A, WAV, FLAC, OGG and video
- Any mix
- 128 to 320 kbps, or 16 to 32-bit
- MP3 or WAV
How do you combine audio files into one?
Open the audio joiner, add two or more files and drag them into order. Cut any part to the stretch you want, choose back to back, a short silence or a crossfade between parts, and leave loudness matching on. Then save the joined file as an MP3 or a WAV.
Use the audio joiner in three steps
Combine audio files, from two voice memos to a whole set of songs.
Add the files
Drop in two or more recordings, songs or videos, in any mix of formats.
Order and set them
Drag the parts into place, cut each one if needed and choose what goes between them.
Save one file
Download an MP3 or a WAV, named after the first part with "joined" added.
An audio joiner that makes the parts sound like one
Order, the joins and the levels, set the way you want them.
Put them in order, cut each one
Drag the parts into order or move them with the arrows. Open any part to cut it to the stretch you want, with the same waveform editor as the trimmer, including one click to cut the silence at its ends.
Back to back, a gap or a crossfade
Back to back joins the parts as they are. A gap puts up to 5 seconds of silence between them, as a pause between speakers. A crossfade of up to 10 seconds blends the end of one part into the start of the next, as a DJ mix does.
One loudness for every part
Each part is measured the way broadcasters measure sound (EBU R128) and brought to −16 LUFS, the level Apple recommends for podcasts, or −14 LUFS for music. A part is raised by at most 15 dB, so the room noise of a very quiet recording is not pushed up too far.
Merge audio files of any format
MP3, M4A, WAV, FLAC and OGG go together, and so does the sound of MP4 and MOV videos. Different sample rates are converted to the highest one, and a mono part joined with stereo ones plays in both ears.
Fades at the start and end
Fade in at the beginning of the joined file and fade out at the end, up to 10 seconds each, so a mix starts and stops smoothly.
Straight on to the next tool
The joined file can go straight to the transcriber or the vocal remover in the studio, without downloading it first.
Audio joiner samples
Three joins made from this site’s own tracks and recordings by the audio joiner in the studio: listen to each result and see how every part was levelled.
Joined on your own device
What the audio joiner does with your files.
Your browser does the joining
Every part is decoded, levelled and joined on your phone or computer.
Never uploaded
Recordings of lessons, meetings and family stay in your own folders.
No account
Join as many files as you like without signing up.
No watermark
The joined file holds your parts and nothing else.
Audio joiner guide: gaps, crossfades and loudness
Back to back, a gap or a crossfade
What goes between the parts depends on what they are. Recordings of one conversation, split by the phone, should run back to back. Separate takes of speech sound natural with a short pause between them. Songs in a mix flow better when one fades into the next.
- 1Speech from separate recordings: a gap of 0.5 to 1 second.
- 2Chapters of an audiobook: a gap of 1 to 2 seconds.
- 3Songs for a party or a workout: a crossfade of 4 to 8 seconds.
- 4An intro jingle into a podcast: a crossfade of 1 to 2 seconds.
Why matching loudness matters
When you combine audio files recorded on different days or devices, one is often much quieter than the next, and listeners reach for the volume at every join. Turning each part up or down by ear rarely gets it right.
LUFS measures loudness the way the ear hears it, over the whole part. The joiner measures each part, then raises or lowers it so all of them land on the same value: −16 LUFS is what Apple recommends for podcasts, −14 LUFS the level Spotify and YouTube play music at.
Leave matching on for speech. For songs mastered together on one album, switch it off to keep the quiet and loud tracks as the artist meant.
Joining different formats and sample rates
A phone recording might be an M4A at 48 kHz, a song an MP3 at 44.1 kHz and a studio take a WAV at 96 kHz. The joiner decodes each part and converts them to the highest sample rate among them, so nothing is lost on the way.
If any part is stereo, the result is stereo and mono parts play in both ears. If every part is mono, the result stays mono, which halves the size of a spoken recording.
Joining the chapters of an audiobook or a course
Long projects are usually recorded in pieces. Name the files so they sort in order (01, 02, 03), add them all at once and check the order in the list.
- 1Cut the silence at the ends of each chapter, so every gap is the one you set.
- 2Choose a gap of 1 to 2 seconds and leave loudness matching at −16 LUFS.
- 3Save an MP3 at 128 kbps for speech, or a WAV to keep editing.
An MP3 joiner on the command line, or a desktop editor
To merge audio files on the command line, list them in a text file, one file 'part1.mp3' line each, then run ffmpeg -f concat -safe 0 -i list.txt -c copy joined.mp3. That only works when every file has the same format and settings, and adds no gaps, fades or levelling.
In a desktop audio editor, import every file, line the clips up end to end on one timeline, and export. Crossfades and loudness have to be set by hand on each track.
What people use an audio joiner for
Several files in, one file out.
Podcast episodes
Put the intro music, the conversation and the outro together at one level.
Audiobook chapters
Join chapters recorded on different days into one file to share.
Party and wedding mixes
Combine songs with crossfades for the first dance and the evening.
Dance and workout sets
Blend the tracks of a routine into one mix without silent breaks.
Lectures in parts
Merge a lecture recorded in several pieces into one recording.
Voice memos
Combine audio files from your phone into one message or note.
Audio joiner FAQ
More audio tools
Open the audio joiner
Add your files to the audio joiner, set the order and the joins, and save one file, free in your browser.