Audio Trimmer

Cut the part you want from an MP3, WAV, M4A, OGG or FLAC file on a waveform, add fades and save as WAV, MP3 or M4A, all in your browser with no upload.

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About this tool

What is the Audio Trimmer?

Drop in an audio file and this trimmer draws its waveform. Drag the two orange handles, or type the start and end times, to select the part you want, add a fade in and fade out so it does not start or stop with a click, preview it, and save it as WAV, MP3 or M4A.

Everything happens in your browser. The file is decoded by your browser's own audio engine, WAV files are written directly in the page, and MP3 or M4A are encoded with ffmpeg compiled to WebAssembly in the same tab, so nothing is uploaded and the tool keeps working on a slow connection once loaded.

  • Waveform with draggable start and end handles
  • Typed start and end times to the hundredth of a second
  • Fade in and fade out, linear or quadratic
  • Preview the selection with fades applied
  • Save as 16-bit WAV, MP3 or M4A, mono option and peak normalise for WAV
  • Runs locally: files are never uploaded
Read the guide: How to Trim Audio Cleanly: Cuts, Fades and Formats

How to use the Audio Trimmer

  1. Drop an MP3, WAV, M4A, OGG or FLAC file on the box, or try the sample tone.
  2. Drag the orange handles on the waveform, or type start and end times such as 12.5 or 1:02.5.
  3. Press Play selection to hear the clip with its fades, and adjust until it sounds right.
  4. Set the fade-in and fade-out lengths and shape, and choose WAV, MP3 or M4A with a bitrate.
  5. Press Trim and save, preview the result, and download it.

Worked examples

Ringtone from a song

Input

MP3, select 0:45.00 to 1:15.00, fade in 0.5 s, fade out 2 s, MP3 192 kbps

Output

30 s MP3 of about 720 KB

192 kbps × 30 s ÷ 8 = 720,000 bytes. Use M4A for an iPhone ringtone file after renaming it to .m4r.

Clean voice memo

Input

M4A memo, cut the first 3 s and the last 5 s of silence, 10 ms fades, WAV

Output

WAV at the decoded sample rate, about 10 MB per minute in stereo at 44.1 kHz

WAV keeps full quality for later editing; mix to mono to halve the size of a voice recording.

Podcast teaser

Input

45 s selection, fade in 1 s, fade out 3 s quadratic, normalise to −1 dBFS, WAV

Output

Teaser clip with peaks at −1 dBFS

Normalising raises the whole clip so its loudest peak sits just under full scale without clipping.

Background and insight

Opening a compressed file for editing means decoding it to plain samples, the same 32-bit floating-point numbers your speakers eventually receive. The trimmer uses the Web Audio API's decodeAudioData for that, which handles MP3, AAC in M4A, WAV, FLAC, Ogg Vorbis and Opus in current browsers (some formats vary between browsers). The decoded audio is at the sample rate the browser chooses, usually 44.1 or 48 kHz, and the waveform shows the peak level of every slice of time.

WAV output is uncompressed 16-bit PCM, written sample for sample from the selection, so it is the right choice when you will edit further: there is no new generation of lossy compression. MP3 and M4A outputs are re-encoded from your original file by ffmpeg, seeking to the start time and limiting the length, with the LAME MP3 encoder or ffmpeg's AAC encoder. Re-encoding a lossy file loses a little quality each time, so pick a bitrate at or above the source.

Cutting a waveform anywhere except at a zero crossing creates a sudden step, heard as a click. Short fades remove it: 5 to 20 milliseconds is enough for a clean edit, half a second to a few seconds for a musical fade. Linear fades sound abrupt at the end for music; the quadratic shape starts more gently and suits long fade-outs.

Common use cases

  • Ringtones and alert sounds

    Cut the hook of a song or an effect to the length a phone accepts.

  • Podcast and interview clips

    Pull a quote for social media or a trailer with clean fades.

  • Voice memos and lectures

    Remove dead air and false starts before sharing a recording.

  • Samples for music and video

    Extract a loop or sound effect as WAV for a DAW or video editor.

Tips and limitations

  • Keep at least a 5 to 10 ms fade on every cut edge to avoid clicks, even when you do not want an audible fade.
  • Choose WAV if you will edit the clip again; choose MP3 or M4A only for the final copy.
  • Re-encoding cannot add quality. Saving a 128 kbps MP3 at 320 kbps only makes the file larger.
  • Very long files take memory to decode: about 21 MB per minute for stereo at 44.1 kHz in the browser, so trim multi-hour recordings on a computer with plenty of RAM.
  • The MP3 and M4A encoders download a 32 MB engine on first use; WAV export needs nothing extra.
  • To cut audio out of a video file, use the MP4 to MP3 converter first or drop the video here if your browser can decode its audio.

Frequently asked questions

How do I cut part of an MP3 without software?

Open the trimmer in a browser, drop the MP3, drag the handles around the part you want, and save. It runs in the page, so there is nothing to install.

Does trimming an MP3 reduce its quality?

Saving as WAV keeps exactly the decoded audio. Saving as MP3 or M4A re-encodes it, which loses a little quality, usually inaudible at 192 kbps or more if the source was good.

Is my audio uploaded anywhere?

No. Decoding, trimming and encoding all run in your browser tab. For MP3 and M4A the page downloads the ffmpeg engine once from a public CDN; your file is never sent.

How long should a fade out be?

For music, 2 to 5 seconds sounds natural. To hide a cut in speech, 10 to 50 milliseconds is enough.

Why is there a click at the start of my clip?

The cut landed where the waveform was not at zero, so it jumps. Add a short fade in of a few milliseconds and the click goes away.

Which audio formats can I open?

Whatever your browser can decode: MP3, WAV, M4A and AAC, FLAC, Ogg Vorbis and Opus in current Chrome, Edge and Firefox. Safari handles most of these but not every Ogg file.

Is there an in-depth guide to the Audio Trimmer?

Yes. “How to Trim Audio Cleanly: Cuts, Fades and Formats” covers the background, how it works, common pitfalls and worked examples. Read the full guide.

People also search for

  • cut the first 10 seconds off an mp3
  • trim a voice memo before sending it
  • make a 30 second clip from a song with fade out
  • audio cutter that works offline in the browser
  • remove silence at the end of a recording
  • trim a wav file without losing quality
  • cut a podcast clip for social media
  • shorten an m4a recording on a computer

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