Free online AUP3 to FLAC converter

What the AUP3 format is

.aup3 is the native project format used by Audacity 3.x. It stores project information such as track layout, labels, effects, clips, and audio data in a SQLite-based database. You encounter it after saving a recording or multitrack editing session in Audacity; it is not intended for direct playback in ordinary media players.

Opening an AUP3 file requires Audacity, normally the same application that created or last saved the project. An AUP3 file can preserve editable project structure, while an exported FLAC file contains rendered audio and does not retain tracks, labels, effect settings, or undo history as editable project elements.

What the FLAC format is

FLAC, or Free Lossless Audio Codec, compresses PCM audio without discarding samples. It produces smaller files than WAV or AIFF while preserving the exact audio data represented by the export.

FLAC is suitable for archival copies, music libraries, playback on compatible computers and devices, and further editing. Support is broad but not universal; some older hardware, video editors, and music applications accept WAV more reliably.

How to convert AUP3 to FLAC

Using Audacity

1. Install and open Audacity, then choose File → Open and select the .aup3 project.
2. Allow the project to finish loading and verify that the tracks, clips, and sample rate are correct.
3. To export everything, leave the whole project selected. To export only part of it, select the required time range; to export specific tracks, use Audacity's track-selection controls before exporting.
4. Choose File → Export Audio.
5. Set the output filename and destination, select FLAC as the format, and choose the desired FLAC compression level if Audacity displays that option. Compression level changes encoding speed and file size, not audio quality.
6. Choose Export, review the metadata dialog, and save the resulting .flac file.

Audacity may mix multiple audible tracks into one FLAC stream during export. If separate files are required, mute or solo tracks and export them individually, or use the relevant multiple-file export option.

Using the online converter

You can also convert the file for free on the 101convert.com website without installing software. Upload the AUP3 file, select FLAC if the converter offers that output, start the conversion, and download the result. Uploading a project transfers its recorded audio to a third-party service, so use Audacity for confidential recordings or projects that the service cannot process.

Quality and compatibility limitations

FLAC export is lossless from Audacity's rendered output, but it cannot restore quality already lost in an MP3, AAC, or other lossy source inside the project. Effects, volume changes, panning, and track mixing are rendered into the exported audio; they are not retained as independently editable operations.

Check Audacity's project sample rate and export settings before saving. Exporting stereo material as stereo preserves its channel arrangement, while a mono project produces a mono FLAC. Keep the original .aup3 file if you may need to revise the session later.