Convert audio without uploading your songs
Change the format of your audio, adjust quality and normalize loudness without sending songs to any server.
What it does
The browser decodes the input file with Web Audio and re-encodes it in a local Web Worker. You can choose MP3 at different bitrates or 16-bit PCM WAV, plus mono or stereo, sample rate and peak normalization.
The input format depends on what your browser can decode. Modern Chrome, Edge and Firefox cover MP3, WAV, OGG, M4A/AAC and FLAC; some proprietary formats may fail.
How to use it
- Open Convert audio.
- Add one or several audio files.
- Choose MP3 or WAV output and adjust quality, channels and sample rate.
- Enable normalization if the volume is uneven.
- Press “Convert audio” and download the files.
Why ConvUp
MP3 or WAV
Compressed for sharing or lossless for editing.
Local processing
Decoding and encoding happen on your device.
Several files
Up to 20 audio files, 15 minutes and 200 MB per file.
Convert audio without uploading the recording
The file is decoded with the browser audio APIs and re-encoded in a local Web Worker: it never travels to a server. You can switch between MP3 and WAV and pick the bitrate; the work happens while the tab stays open, so an hour-long recording takes far longer than a two-minute clip.
Every lossy conversion throws information away: converting MP3 to MP3 or raising the bitrate of an already compressed file does not bring back the lost quality, it only makes the file bigger. If you plan to edit the audio, work in WAV and convert to MP3 at the very end.
Turning a WhatsApp voice note into an MP3
WhatsApp voice notes are stored as .opus files inside an OGG container, and plenty of players, editors and websites will not open them. Download the note from the chat (long-press the message and pick Save or Share), upload it here and choose MP3: the audio is decoded in your browser and you get a file that plays anywhere.
A note that lasts several minutes takes longer to convert; keep the tab open until the result appears. For maximum quality export to WAV; to forward it by email or another app, MP3 at 128 kbps is more than enough and takes far less space.
Frequently asked questions
Are my songs uploaded?
No. Audio is decoded and encoded in the browser with Web Audio and a local Web Worker. There is no upload to a conversion server.
Which output format should I choose?
MP3 if you want a small file to share; WAV if you need maximum quality or plan to keep editing.
Why does a format fail?
Input support depends on the browser decoder. Try converting the file to WAV or MP3 with another app and then retry.
Is there a duration limit?
Yes: 15 minutes per file, 20 files and 200 MB per file. The limits protect browser memory.