What does Audio Cutter do?
Trim audio in your browser: WAV, MP3, M4A, OGG, FLAC or AAC. Drag waveform handles, preview, add fades, keep the format or convert. No uploads.
- Price
- Free
- Account
- Not required
- Processing
- Entirely in your browser; your data and files are not uploaded
- Works on
- Any modern browser on desktop, tablet or phone
- Category
- Video and Audio Tools
How to use the audio cutter
- Drop an audio file (MP3, WAV, OGG, FLAC, M4A or AAC, up to 100 MB).
- Select the part to keep by dragging the handles on the waveform or typing start and end times.
- Preview with Play selection. Optionally add fades or choose a different output format.
- Choose Fast (copy) or Exact (re-encode), click Cut and download the result.
How it works
The waveform is decoded with the Web Audio API at 8 kHz and drawn from per-slice peaks. FFmpeg cuts with -ss before the input and -t for the length. With "Same as the input", Fast mode copies the encoded audio (-c:a copy) into the same format; Exact mode, a format change or fades re-encode with the matching encoder (LAME, AAC, Vorbis, Opus, FLAC or 16-bit PCM) and afade.
Assumptions
- Fast mode snaps to the audio frame size of the codec (for example about 21 ms for AAC and 26 ms for MP3); WAV and FLAC copies can end a few hundredths of a second after the selection; choose Exact for sample-accurate edges.
- Re-encoding MP3, AAC, OGG or Opus is lossy; WAV and FLAC outputs are lossless.
Frequently asked questions
Are my files uploaded?
No. The file is processed by FFmpeg compiled to WebAssembly, running inside your browser. Only the engine itself is downloaded (once, from cdn.jsdelivr.net); your video, audio or images never leave your device.
Does cutting reduce quality?
Not in Fast mode, which copies the original data. Exact mode decodes and re-encodes, which adds a small loss for lossy formats. WAV and FLAC stay lossless either way.
Why can't I see a waveform?
The waveform uses your browser's own decoder. If it cannot decode the format (for example some AAC or FLAC files in older Safari), you can still type the times and FFmpeg will cut the file.
Why does the first run take longer?
The first time you use any of the video and audio tools, your browser downloads the FFmpeg engine, about 31 MB. It is stored in your browser, so later runs on this device start without downloading it again unless you clear site data.
Limitations
- FFmpeg runs as single-threaded WebAssembly in the browser, which is much slower than desktop FFmpeg. Processing time depends on the file length, resolution and your device; long HD videos can take many minutes.
- Files up to 100 MB are accepted.
- Only the first audio track is kept, and cover art is dropped.
- One selection per run.