Audio Converter

Audio formats multiply fast: voice notes arrive as M4A or OPUS, podcast exports as WAV, old downloads as OGG or FLAC, and the device or app on the receiving end wants plain MP3. Online converters that upload your recordings to a server are slow for big files and questionable for private conversations.

This audio converter works in your browser. It decodes MP3, WAV, M4A/AAC, OGG, Opus, FLAC and WebM audio, and writes MP3 (with a LAME encoder) or uncompressed WAV. You can also change the sample rate or mix down to mono, which is useful for speech-recognition tools and small voice files.

Multiple files convert in one batch, each result listing its length, channel count and sample rate so you can confirm the output before downloading.

If you mainly deal with one specific pair of formats, the dedicated MP3 to WAV and WAV to MP3 pages use the same engine with fewer options to think about.

How It Works

1. Add audio files — up to 20 at once. The browser's Web Audio API decodes each file into raw 32-bit float samples; if a codec isn't available in your browser you get a clear message naming the file.
2. Choose output settings — MP3 (48–320 kbps) or WAV (16- or 24-bit PCM), plus optional sample-rate conversion (48, 44.1, 22.05 or 16 kHz) and stereo/mono. Resampling is done with an OfflineAudioContext.
3. Encode and save — MP3 is encoded with lamejs, a JavaScript port of the LAME encoder; WAV is written directly as PCM. Progress is shown, the job can be cancelled, and results download singly or as a ZIP.

Compatibility & Support

Supported Input → Output Formats

• Input: MP3, WAV, M4A, AAC, OGG/OGA, OPUS, FLAC, WEBA/WebM audio, AIFF (browser-dependent)
• Output: MP3 (CBR 48–320 kbps) or WAV (PCM 16/24-bit)
• Options: sample rate 16–48 kHz, stereo or mono

Unsupported Formats

Decoding uses your browser's built-in codecs. Chrome and Edge read MP3, WAV, AAC/M4A, OGG Vorbis, Opus, FLAC and WebM audio; Firefox is similar but has no AAC on some Linux systems; Safari reads MP3, AAC/M4A, WAV, FLAC and, from recent versions, Opus.

WMA, AMR and AC-3 are not decoded by most browsers. DRM-protected files (for example Apple Music downloads) cannot be converted. Metadata such as ID3 title, artist and cover art is not carried over to the new file.

File Size Limits

Up to 20 files per batch and 300 MB per file. Audio is decoded to uncompressed samples in memory, so a one-hour stereo recording needs roughly 1.3 GB of RAM while it is processed. On phones, split long recordings or convert them one at a time.

Who Should Use This Tool?

• Students: A student converts lecture recordings from M4A to MP3 so an older MP3 player and a transcription tool can both read them.
• Freelancers & Designers: A video editor converts a client's OPUS voice notes to 48 kHz WAV so they drop cleanly onto a Premiere or DaVinci timeline.
• Office Professionals: A team lead converts a batch of meeting recordings to 64 kbps mono MP3 to fit them in a shared drive with limited space.
• Developers: A developer prepares 16 kHz mono WAV samples for a speech-to-text model without installing FFmpeg.

Why This Tool Beats the Alternatives

• No upload wait for large WAV files — conversion starts immediately.
• Private by design: interviews and voice notes never leave your device.
• Free batch conversion with no length limit per file.
• Speech-friendly options (16 kHz mono) that many converters hide.
• Clear codec messages instead of silent failures.

Pro Tips

• For music, 192 kbps MP3 is indistinguishable from the original for most listeners; use 320 kbps only for archiving.
• For voice, mono at 64–96 kbps halves the size with no loss in clarity.
• Converting MP3 to WAV makes an editable file but can't restore quality lost in the MP3 — keep originals if you have them.

Drop your audio files above, choose MP3 or WAV, and download the converted tracks.