Split audio into parts: how to split a large audio file
Three ways to split a long recording into equal parts or fixed-length chunks: in your browser, in Audacity, or with one ffmpeg command, without cutting words in half.
On this page
In short
- Up to an hour long: the free audio splitter in your browser splits audio into up to 20 parts, by number of parts or every few minutes.
- Longer recordings: use Audacity (free, desktop) or one ffmpeg command.
- Avoid cutting words in half: split at pauses, and add a few seconds of overlap.
- Splitting just to transcribe? You may not need to: files up to 5 hours can be uploaded whole.
Long recordings run into limits: upload caps, email size limits, or a part you want to send on its own. This guide shows three ways to split audio into parts, how to choose the length of each part, and how to avoid cutting a sentence in half. To shrink a file instead, see how to reduce audio file size.
Why split audio at all?
- Upload or attachment limits. A website or email won't take a file that big.
- Sharing one section. Send the part of a meeting someone needs, not all of it.
- Chapters. Turn a lecture, sermon or podcast into separate tracks.
- Working in sessions. Listen to or edit a long interview in manageable pieces.
Option 1: split audio in your browser
The free audio splitter works on recordings up to an hour long and 200 MB, with nothing to install.
- Open the audio splitter and choose the file: MP3, M4A, WAV, or the sound from a video.
- Under Split by, choose Number of parts or Every N minutes.
- Set an overlap, for example 5 seconds, so a sentence that falls on a split point is complete in at least one part.
- Leave Split at natural pauses on. Each split point moves to the quietest moment nearby, so parts end between sentences.
- Drag any split point on the waveform to adjust it, then download the parts one by one or all together as a ZIP.
You can make up to 20 parts, each at least 10 seconds long. The file is split by your browser and never leaves your device.
You may not need to: upload recordings up to 5 hours or 1 GB whole, and read the first part free.
Upload a recordingOption 2: split audio in Audacity
Audacity is a free desktop audio editor for Windows, Mac and Linux, and it handles recordings of any length.
- Open the file in Audacity.
- Click where you want a split, and add a label (Edit › Labels › Add Label at Selection, or Ctrl+B). Repeat for every split point.
- Export each labelled section as its own file. In recent versions, choose File › Export Audio and pick Multiple files; in older versions, use File › Export Multiple.
Zoom in on the waveform and put each label in a gap between words.
Option 3: split audio with ffmpeg
If you're comfortable with a command line, ffmpeg splits a file into equal chunks in seconds, without re-encoding:
ffmpeg -i recording.mp3 -f segment -segment_time 1800 -c copy part%03d.mp3This makes 30-minute parts (1800 seconds) called part000.mp3, part001.mp3 and so on. Change 1800 for a different length. Because nothing is re-encoded, the quality stays the same, but splits land on the nearest frame, not at a pause.
Split by time or by size?
Most tools split by time. To hit a size limit instead, work it out from the bitrate: an MP3's size in MB per hour is about its kbps × 0.45. A 128 kbps MP3 is about 58 MB an hour, so for a 25 MB email limit, parts of about 25 minutes fit.
| Bitrate | MB per hour | Minutes per 25 MB |
|---|---|---|
| 32 kbps (voice, smallest) | 14 | about 100 |
| 64 kbps | 29 | about 50 |
| 128 kbps | 58 | about 25 |
| 320 kbps | 144 | about 10 |
Often it's easier to compress first: the free audio compressor can make an hour of speech small enough for one email.
Naming and keeping track of parts
- Number parts with leading zeros (part01, part02 ... part10) so they sort in order.
- Put the start time in the name, such as
lecture_part02_00-30-00.mp3, if people will jump to a section. - Keep the original file until you've checked that every part plays to the end.
Joining the parts back together
Need one file again? The free audio joiner puts up to 20 clips back together in your browser, in the order you choose.
Splitting for transcription
On Allnote on the go, a single file can be up to 5 hours or 1 GB, so most recordings don't need splitting. If you do split audio, for example to transcribe only some sections, upload the parts together: up to 20 files at once are priced as one order. The audio splitter's Transcribe all parts button does this for you.
What it costs
The splitter, joiner and compressor are free. Transcription is paid per file, after a free preview.
Prices today
| Option | Price | Good for |
|---|---|---|
| Preview | Free | Half the recording, up to 5 minutes. No account. |
| Pay per file | 10¢ a minute, $3 minimum per order | One longer file. Files uploaded together share one minimum. |
| Credit pack | $9 for 90 min · $19 for 240 min · $49 for 12 h | Lots of files. Credits never expire. |
The exact price is shown before you pay. See all prices
Questions
How do I split audio into equal parts?
In the free audio splitter, choose Number of parts and pick how many. Each part is about the same length, with split points moved to nearby pauses.
What's the best length for each part?
It depends on why you split audio. For email, work back from the size limit; for listening, 20 to 30 minutes is easy to follow; for chapters, split where the topic changes.
Can I split audio longer than an hour?
Not in the browser splitter, which handles up to an hour. Use Audacity or ffmpeg for longer recordings.
Does splitting lower the quality?
The browser splitter saves new files, and ffmpeg with -c copy doesn't re-encode at all, so the quality stays the same.
Is my file uploaded when I split it?
No. The audio splitter runs in your browser, and the file never leaves your device.
Free splitter in your browser, or upload up to 5 hours for a transcript.
Split audioWritten with AI help.
Reviewed by Mubashar Rafique on 12 Oct 2026.