Audio Trimmer

Free Audio Trimmer with Visual Waveform Editor

Toololis Audio Trimmer lets you cut and trim audio files directly in your browser with a visual waveform editor. Upload any audio file, see its waveform displayed on a canvas, drag the start and end markers to select the portion you want to keep, preview the selection, and download the trimmed audio as a high-quality WAV file. No software to install, no sign-ups, and your audio never leaves your device.

This tool is perfect for quick audio edits: trimming silence from the beginning or end of a recording, extracting a specific section from a podcast or interview, cutting a ringtone from a song, or preparing audio samples for a project. The visual waveform makes it easy to identify exactly where to cut.

How Audio Trimming Works

When you upload a file, the tool uses the Web Audio API's AudioContext.decodeAudioData() to convert the compressed audio (MP3, OGG, etc.) into a raw AudioBuffer — an array of floating-point samples for each channel. The waveform is drawn by sampling this buffer and rendering amplitude values on an HTML5 Canvas.

When you set trim points, the tool creates a new AudioBuffer containing only the samples between your start and end positions. This trimmed buffer is then encoded as a WAV file with proper RIFF headers and PCM data, which you can download. The process is sample-accurate and lossless (for the selected portion).

Supported Input Formats

• MP3 — the most common audio format, universally supported by all browsers.
• WAV — uncompressed audio, supported everywhere, produces the largest files.
• OGG Vorbis — open-source compressed format, supported in Chrome, Firefox, Edge.
• WebM Opus — modern compressed format, excellent quality at small sizes.
• AAC / M4A — used by Apple devices, supported in most browsers.
• FLAC — lossless compressed, supported in Chrome and Firefox.

Why Output is WAV

The trimmed audio is exported as WAV (uncompressed PCM) because encoding to lossy formats like MP3 requires external libraries such as LAME, which would significantly increase the tool's download size and complexity. WAV preserves the full quality of the trimmed selection and is compatible with every audio player and editor. If you need a different format, you can convert the WAV using the Audio Converter tool or any desktop audio editor.

Tips for Precise Trimming

• Zoom into the waveform mentally — quiet sections appear flat, loud sections show peaks. Use these visual cues to find the right cut points.
• Use the time input fields for exact positioning. Type the desired start and end times to the nearest 0.1 second.
• Always preview your selection before downloading — click "Play Selection" to hear exactly what will be saved.
• If the waveform is mostly flat, your audio may be very quiet. The tool normalizes the display to show whatever amplitude is present.
• For long files, the markers may feel coarse. Use the time inputs for fine control.

Common Use Cases

• Podcast editing — remove intro silence, trim end chatter, extract a highlight clip.
• Ringtone creation — select 20-30 seconds from a song and save as WAV (convert to M4R for iPhone afterward).
• Audio sample preparation — cut clean loops and samples for music production.
• Voice recording cleanup — remove false starts, coughs, and dead air from voice memos.
• Lecture excerpts — extract a key section from a long recording for study or sharing.

File Size and Memory

Decoding audio into an AudioBuffer uses approximately 10 MB of memory per minute of stereo audio at 44.1kHz. A 5-minute MP3 file that is only 5 MB on disk will expand to roughly 50 MB in memory when decoded. Most modern devices handle files up to 30 minutes without issues. For very long files, consider using desktop software instead.