Audio Converter
Convert audio between MP3, WAV, M4A/AAC, OGG, Opus, FLAC and AIFF — entirely in your browser, nothing uploaded.
Fast mode uses your browser's built-in decoder — instant, private and offline, with WAV and MP3 output. Switch to Advanced for AAC, OGG, Opus, FLAC and AIFF.
Drop audio files here or click to choose
MP3, WAV, M4A, AAC, OGG, Opus, FLAC, AIFF · files never leave your device
100% private:every conversion runs in your browser — your audio is never uploaded to a server. Fast mode uses the browser's native decoder (WAV/MP3). Advanced mode loads FFmpeg.wasm from a CDN on first use for extra formats; some exotic input codecs (e.g. certain WMA files) or output codecs may not be available in the WebAssembly build, in which case that file is skipped with a note.
What Is the Audio Converter?
The Audio Converter changes audio files from one format to another right in your browser — your files are never uploaded to a server. It has two engines. Fast mode uses your browser's built-in decoder to read almost any common audio (MP3, WAV, M4A, AAC, OGG, Opus, FLAC and more) and re-encode it to WAV or MP3 instantly, even offline. Advanced mode loads FFmpeg (compiled to WebAssembly) on demand to unlock more output formats — AAC/M4A, OGG Vorbis, Opus, FLAC and AIFF — and to read a wider range of inputs. You can drop in several files at once, pick a target format and (for MP3, AAC, OGG and Opus) a bitrate, convert the whole batch, and download the results individually or all together. It's a private, no-signup alternative to upload-based converters for the everyday job of turning an M4A voice memo into an MP3, a WAV master into a compressed MP3, or a FLAC into something your phone plays.
How It Works
Choose Fast (WAV/MP3, instant) or Advanced (more formats), pick the format to convert to and a bitrate if it applies, then drop your audio files in and press Convert. Download each result or use Download All. Everything happens on your device.
When to Use It
Use it to turn iPhone M4A recordings into MP3, shrink WAV masters to MP3 for sharing, convert FLAC to MP3/AAC for your phone, prepare OGG or Opus for the web, or extract a compatible audio file for editing.
Frequently Asked Questions
- Are my files uploaded anywhere?
- No. All conversion happens locally in your browser using the Web Audio API (Fast mode) or FFmpeg compiled to WebAssembly (Advanced mode). Your audio never leaves your device.
- What's the difference between Fast and Advanced mode?
- Fast mode uses the browser's native decoder and outputs WAV or MP3 instantly with no download. Advanced mode loads FFmpeg (~25 MB the first time) to support more output formats like AAC/M4A, OGG, Opus, FLAC and AIFF. On the mobile apps Fast is the default; on the website Advanced is.
- Can it convert WMA or video files?
- Advanced mode can read many formats including some video (to extract audio), but a few proprietary codecs like WMA aren't always available in the WebAssembly build; those files are skipped with a note. For the common MP3/WAV/M4A/FLAC/OGG jobs it works great.
- Is there a file-size limit?
- Only your device's memory — large files use more RAM since everything is processed in the browser. Very large files convert faster in Fast mode.
Last reviewed: 2026-06-27