Are my audio recordings uploaded to an online server?

No. The entire audio decoding and MP3 encoding pipeline runs directly in your browser using the HTML5 Web Audio API and pure JavaScript. Your private audio never leaves your device.

Why is OGG format not universally converted on all devices?

OGG Vorbis audio decoding is supported natively by Chrome, Firefox, and Edge, but Apple Safari and iOS WebKit do not support OGG decoding in the Web Audio API. To ensure dependable results across all operating systems, we recommend WAV and MP3.

What bitrate should I choose for MP3?

192 kbps offers the best balance of transparent CD-like audio quality and compact file size. 320 kbps provides maximum audio fidelity, while 128 kbps is suitable for spoken word podcasts and voice notes.

Universal Audio Converter

Online Audio Format Converter

Convert sound files between WAV, MP3, and browser-supported formats directly in your browser. Fast local encoding, customizable bitrates, and 100% privacy with zero server uploads.

Select or Drop Audio File

Supports MP3, WAV, M4A, and AAC (up to 100MB). Processed 100% locally in your browser.

Runs entirely in your browser — nothing is uploaded

100% Browser-Side Processing

Unlike conventional audio conversion websites that upload your voice recordings, songs, or interviews to remote servers, FreeFileTool executes the entire conversion locally using Web Audio API and LAME MP3 encoding.

Format & Device Compatibility

WAV and MP3 are decoded natively across all modern desktop and mobile browsers. M4A/AAC files are supported on WebKit and Chromium browsers. OGG decoding depends on operating system codec availability.

WAV vs. MP3 Guide

Unsure whether you need lossless PCM or compressed MP3? Read our full technical comparison: WAV vs MP3: Which Audio Format to Use? →

Online Audio Format Converter

Select or Drop Audio File

Audio Processing Complete!

100% Browser-Side Processing

Format & Device Compatibility

WAV vs. MP3 Guide

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