Best free audio tools, and how to choose one

Not all free tools are free in the same way. Some are free until you download. Here is what to look for, and our picks for the jobs people do most.

What makes an audio tool good

Your file stays private. Tools that run in your browser never upload your file. Tools that run on a server keep a copy, at least for a while. That matters most for unreleased music and private recordings.
No account for everyday jobs. Trimming a voice memo should not need a password.
No watermark, no ransom. Audio tools sometimes hold the download hostage behind a paywall after the work is done. The finished file should just download.
Fast on a phone. Most quick audio jobs start on a phone, in a hurry.
Honest limits. A good tool says what it cannot do, in plain words, before you start.

Our picks, job by job

Posting audio to video platforms: MP3 to MP4 with Image turns a track plus cover art into a postable video.

Converting: WAV to MP3, M4A to MP3, FLAC to MP3, OGG to MP3, and MP3 to WAV cover the format shuffle in one engine.

Editing on the fly: the MP3 Cutter and Audio Joiner handle trims and merges, and the Ringtone Maker exports in the format your phone wants.

Fixing and sizing: Volume Booster rescues quiet recordings, and Compress MP3 shrinks files for email and messaging limits.

For DJs and producers: BPM and Key Finder reads tempo and key, and the Pitch and Tempo Changer shifts one without touching the other.

Other good options: Audacity is a superb free desktop editor when you need deep, multi-track work, and it is hard to beat for long projects. For a one-off job on a phone, a browser tool that never uploads your file usually wins on speed alone.