Audio Trimmer

Trim, cut, and split audio files in your browser. Visual waveform editor with fade-in/out, no upload required. Supports MP3, WAV, OGG, FLAC, M4A, and WebM.

Processed locally

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How to Use

Trim any audio file in three steps:

Upload your audio file — Drop any audio file (MP3, WAV, OGG, FLAC, M4A, WebM) into the drop zone. The file is decoded locally using the Web Audio API — nothing is uploaded to any server.
Select the region to keep — Drag the red handles on the waveform to set the start and end points. You can also type exact times in the precision inputs below the waveform. Click Preview to listen to your selection. Add fade-in/out for smooth transitions.
Trim and download — Click "Trim & Download" to export the selected region as a lossless WAV file. The trimmed audio preserves the original quality with no re-encoding artifacts.

About This Tool

How Audio Trimming Works

This tool uses the browser's built-in Web Audio API to decode audio files into raw PCM (Pulse Code Modulation) samples. The waveform visualization shows peak amplitude for each time segment — taller bars mean louder audio. When you set start and end points, the trimmer extracts exactly those PCM samples and writes them into a new WAV file with a standard RIFF header.

The output is always WAV (16-bit PCM) because trimming should be a lossless operation. Re-encoding to MP3 or AAC after trimming would introduce generation loss — quality degradation from re-compression. If you need a compressed format, trim first, then convert using a dedicated audio converter.

Fade-In and Fade-Out

Abrupt cuts at trim points can produce audible clicks or pops, especially with sustained sounds. Fade-in gradually increases volume from silence over the specified duration, while fade-out reduces volume to silence at the end. Both use a linear amplitude ramp applied directly to the PCM samples. Even a 0.1-second fade is enough to eliminate most click artifacts.

Waveform Visualization

The waveform shows peak amplitude across the audio duration. Peaks close to 1.0 (full height) indicate loud sections, while flat sections near zero indicate silence. The visualization uses the first channel (left in stereo files) for display, but the trimmer preserves all channels in the output. The waveform is divided into 800 segments for efficient rendering — each bar represents the maximum absolute sample value in that time window.

Audio Formats

Input format support depends on your browser's built-in decoders. Chromium browsers support MP3, WAV, OGG, FLAC, AAC (M4A), WebM, and Opus. Firefox supports the same except some AAC variants. Safari supports MP3, WAV, AAC, FLAC, and AIFF. If your file fails to decode, try converting it to WAV or MP3 first. For recording audio, see Screen Recorder.

Why Use This Tool

Zero-Upload Audio Editing

Most online audio trimmers upload your file to a server for processing. This tool processes everything locally in your browser — your audio never leaves your device. This means faster processing (no upload/download wait), complete privacy (no server-side storage), and no file size restrictions from server limits.

Common Use Cases

Ringtone creation: Cut a 30-second segment from a song for use as a phone ringtone or notification sound.
Podcast editing: Remove silence, intros, or outros from podcast recordings before publishing.
Sample extraction: Extract specific sounds, riffs, or vocal segments from longer recordings for music production.
Voice memo cleanup: Trim the start and end of voice recordings to remove awkward pauses and background noise.
Sound effects: Create precise audio clips from longer sound files for use in videos, presentations, or games.

Privacy

100% client-side processing using the Web Audio API. No files are uploaded, no data is stored, and no network requests are made during trimming. Related tools include Screen Recorder, Camera Recorder, and Base64 File Converter.

FAQ

What audio formats are supported?

The tool supports any format your browser can decode: MP3, WAV, OGG Vorbis, FLAC, AAC (M4A), and WebM audio. Output is always WAV (lossless) to avoid re-encoding quality loss. For lossy output formats, use a separate converter after trimming.

Is there a file size limit?

There's no hard limit, but very large files (over 500MB) may cause memory issues in the browser. The tool decodes the entire file into memory as PCM audio data, which is uncompressed. A 5-minute MP3 (~5MB compressed) becomes roughly 50MB of decoded PCM data in memory.

Why is the output a WAV file instead of MP3?

Trimming audio should not reduce quality. WAV is lossless — it preserves every sample exactly as decoded. Re-encoding to MP3 would introduce generation loss (quality degradation from re-compression). If you need MP3 output, trim first as WAV, then convert using an audio converter.

How does the fade-in/out work?

Fade-in gradually increases volume from silence to full over the specified duration at the start of your selection. Fade-out does the reverse at the end. Both use a linear ramp applied to the PCM samples. This eliminates clicks and pops at the cut points and creates smooth transitions.

Is my audio uploaded to any server?

No. All processing happens entirely in your browser using the Web Audio API. Your audio file never leaves your device. The waveform visualization, trimming, and export are all performed locally in memory.