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Audio Cutter & Trimmer
Crop MP3s, edit speeds, apply volume fades, and export multiple formats completely offline.
Crop MP3s, edit speeds, apply volume fades, and export multiple formats completely offline.
Select any audio file to open the premium DAW waveform editor.
In the early days of web applications, editing sound files was a slow process. Users had to upload their music tracks to remote servers, wait for a back-end script to crop the file, and then download the results. This old method wasted bandwidth, posed serious data privacy risks, and resulted in long processing queues. Today, modern web browsers are equipped with powerful client-side interfaces that can process raw sound waves instantly.
This online editor utilizes the native Web Audio API, allowing all modifications to occur inside the system RAM of your device. When you select an audio track, the browser immediately decodes the binary file into thousands of floating-point data points. By manipulating these numerical values in local memory, we can trim segments, cut sections, boost volume, adjust speed, and fade waveforms in real-time. Since no data is transmitted over the web, your files remain completely private and secure.
Applying transition effects like a fade-in or fade-out is done by multiplying the signal amplitude values against linear or exponential curves. For volume adjustment, the gain node scales every decoded audio frame by a target coefficient. When a user requests to reverse the audio, the script simply swaps the sample indexes in the offline buffer. Adjusting the playback rate shifts the virtual sample rate pointer during the compilation stage, letting you speed up or slow down files cleanly.
Once editing is complete, the final sound buffer is converted back to a downloadable format. A standard WAV export builds a forty-four byte header defining sample channels, rate, and bit depth, before mapping the raw PCM bytes directly. For MP3 compilation, the app loads a lightweight local encoder that converts floating-point data blocks into standard MP3 audio frames right on your device.
Underneath the waveform view sits a fairly complete mini digital audio workstation. Beyond simple trimming, you get a Trim/Cut mode toggle, a volume booster that can push a quiet recording up to 200% of its original level, adjustable fade-in and fade-out ramps with a custom duration in seconds, a mono-downmix checkbox, a full-track reverse effect, a playback-speed modulator from 0.5x to 2x, and a one-click "Auto Trim Silence" button. Live stats above the waveform show peak level, average RMS loudness, and the percentage of the file that is effectively silent, which is genuinely useful for judging how "hot" or how quiet a recording is before you commit to an export.
The waveform itself is rendered by WaveSurfer.js, an open-source visualization library, with its Regions plugin providing the draggable purple selection handles you use to mark your start and end points. Every parameter change — moving a handle, ticking a fade checkbox, nudging the volume slider — is pushed onto an internal undo/redo stack, so experimenting with a cut is never a one-way decision. You can step backward with the Undo button or Ctrl+Z at any point before you export the final file.
You can open MP3, WAV, AAC, M4A, FLAC, OGG, WMA, AIFF, and OPUS files, since the tool relies on your browser's own built-in audio decoder to read them rather than a custom parser. Once decoded, every file — regardless of its original format — becomes the same thing internally: a raw buffer of floating-point PCM samples. That's the key reason effects like volume, fades, reverse, and speed behave identically no matter what format you started from; the editor is never working with compressed MP3 or AAC data directly, only the fully decoded audio.
On export, two different engines are used depending on the format you choose. WAV export builds a standard 44-byte header and writes the PCM samples out directly, which is why it's instant and perfectly lossless. MP3 export runs entirely through lamejs, a pure-JavaScript port of the LAME encoder, so no server or plugin is needed. AAC, OGG, and FLAC exports lean on a WebAssembly build of FFmpeg loaded on demand — this is a heavier download the first time you use one of those formats, and it's why the dropdown labels them "(FFmpeg)" separately from MP3 and WAV.
If you need the absolute highest fidelity — for a master copy, for further editing in another program, or because you're archiving a recording — export as WAV or FLAC. WAV is uncompressed and matches your decoded audio sample-for-sample; FLAC compresses losslessly, so it sounds identical to WAV but produces a noticeably smaller file. Both are the right call whenever quality matters more than file size.
MP3 remains the most universally compatible option, playable on essentially every device and platform without conversion. The bitrate selector runs from 128 kbps up to 320 kbps: 128 kbps is fine for spoken-word content like podcast clips or voice memos where small file size matters most, while 256-320 kbps is a safer choice for music where you want to preserve detail in cymbals, harmonies, and low bass. AAC and OGG sit between MP3 and FLAC in the trade-off — smaller than WAV, generally sounding a little cleaner than MP3 at an equivalent bitrate, and worth choosing if your target platform (many streaming apps, for instance) prefers one of those containers specifically.
The Volume popup boosts or reduces gain from 0% to 200% of the original level, applied as a simple multiplier across every sample in your selection — useful for a phone recording that came out too quiet, though pushing it too high can introduce clipping distortion if the source was already close to full volume. The Fade panel lets you enable a fade-in, a fade-out, or both independently, each with its own duration between one and ten seconds, so a clip starts and ends smoothly instead of with an abrupt pop.
Converting to Mono downmixes stereo audio to a single channel, which slightly reduces file size and is sometimes preferred for voice content or older devices with mono speakers. Reverse plays your selected region backward — useful for sound-design effects or the classic "reversed vocal" trick — and works on the true underlying sample data, not just the visual waveform. The Speed modulator changes playback rate from 50% to 200%; because it works by adjusting the audio's playback rate rather than using separate pitch-shifting, speeding a clip up also raises its pitch and slowing it down lowers it, the same way a physical tape or vinyl record changes pitch when sped up or slowed down.
Zoom in on the waveform using the zoom slider before finalizing a cut point — at the default zoom level it's easy to clip off the very start of a word or a drum hit without realizing it. When trimming spoken content, try to place your start and end handles in the small gaps of silence between words or breaths rather than mid-syllable, which avoids an abrupt, clipped-sounding edit. A short fade-in and fade-out of even half a second can make an otherwise sharp cut sound intentional and polished rather than accidental.
If you're preparing several clips from the same source file, use the Preview Select button to audition each cut before exporting rather than exporting blind — it's much faster to catch a misplaced handle at the preview stage than after downloading. And if you plan to apply multiple effects (say, a volume boost plus a fade), remember they combine into a single render, so check the Peak level stat after adjusting volume to make sure you haven't pushed the signal into distortion territory above 100%.
"My file won't decode." This usually happens with an unusual or corrupted codec variant inside a container your browser doesn't fully support. Try converting the file to standard WAV or MP3 first with another tool, or test with a different source file to confirm the browser's decoder is the limiting factor.
"AAC, OGG, or FLAC export is slow to start." These three formats route through a WebAssembly build of FFmpeg that has to download and initialize the first time you use it in a session — this is a one-time delay per browser tab, and subsequent exports in that session are noticeably faster. If it never finishes loading, your network or browser extensions may be blocking the FFmpeg script from unpkg.com, in which case the app automatically warns you and falls back to native Web Audio processing where possible.
"Auto Trim Silence didn't remove the pause in the middle of my recording." That's expected behavior, not a bug — the feature scans inward from the very start and very end of the file only, moving your selection markers to skip leading and trailing silence. It does not search for or remove quiet gaps in the middle of a track; for that, you'd need to make additional manual cuts.
Full desktop programs like Audacity or Adobe Audition offer far deeper editing — multitrack mixing, spectral repair, VST plugin support — but require a download, an install, and some familiarity with a more complex interface before you can do something as simple as trimming a thirty-second clip. Server-based online cutters, on the other hand, are quick to use but typically require uploading your file to a remote service, which means waiting on your upload speed, trusting a third party with your audio, and often hitting file-size or daily-use caps tied to a free tier.
This tool sits in between: it has enough real editing power — waveform-accurate trimming, fades, volume, mono, reverse, speed, silence detection, and five export formats — to cover the vast majority of everyday audio tasks, while running entirely inside your browser tab with nothing to install and nothing uploaded anywhere. For quick, focused jobs like cropping a podcast clip, making a ringtone, or cleaning up a voice memo, that combination of capability and zero-friction privacy is usually a better fit than either a heavyweight desktop DAW or a server-dependent web uploader.
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Got questions? Find clear answers to how our client-side editor processes your audio tracks.
The tool natively decodes and crops popular audio formats such as MP3, WAV, AAC, M4A, FLAC, OGG, WMA, AIFF, and OPUS. It uses your browser's decoding engine to load these tracks smoothly.
Exporting your edited file as a WAV format saves the waveform in lossless uncompressed PCM format, matching the exact decoded quality of the original file without any re-compression loss.
Since the entire loading, visual rendering, and audio encoding processes are executed locally in the browser sandbox, your files never leave your computer. This protects sensitive recordings from interception.
Trimming keeps the selected area and discards everything else. Cutting removes the selected area entirely and joins the remaining left and right pieces back together.
Yes. The editor has an integrated volume booster popup that allows you to amplify your sound track up to two hundred percent of its original level before compiling.
Auto Trim Silence scans inward from the very start and the very end of your waveform for the first points where amplitude rises above a low threshold, then moves your selection handles to skip the silent leading and trailing margins. It only trims silence at the edges of the file, not quiet gaps in the middle of the recording.
Yes. The Speed Modulator adjusts the audio's native playback rate rather than applying separate pitch-correction, so speeding a track up raises its pitch and slowing it down lowers it, the same way a tape or vinyl record changes pitch when its speed changes.
Yes. Every change to your selection, volume, fades, or other parameters is pushed onto an undo/redo history, so you can step backward with the Undo button (or Ctrl+Z) and forward again with Redo (or Ctrl+Y) at any point before exporting.
Choose WAV or FLAC for the best possible quality (uncompressed and lossless-compressed respectively). Choose MP3 for maximum compatibility with other devices and apps, picking a higher bitrate like 256-320 kbps for music. AAC and OGG are good middle-ground options when a specific platform prefers one of those containers.
No, once the page loads, the app operates completely offline. You can edit, trim, and download files without active internet access, as all operations are done by the local browser code.