Where all those WAV files come from
WAV is the default output of almost everything that records sound seriously: handheld field recorders from Zoom and Tascam, the export dialogs of Audacity, Logic, Ableton and Pro Tools, Windows Sound Recorder, lecture-capture systems and the CDs you ripped years ago. It is a fine format for capture because nothing is thrown away. It is a poor format for keeping, sending and listening, because a single hour weighs around 600 MB.
Converting to MP3 is the standard fix. A podcast episode drops from 500 MB to 70 MB, a day of interview recordings fits in an email, and a sample library finally fits on a phone.
Picking a bitrate
| Content | Suggested bitrate | Size per hour |
|---|---|---|
| Dictation, meetings, voice memos | 64–96 kbps | 29–43 MB |
| Podcasts, interviews, audiobooks | 96–128 kbps | 43–58 MB |
| Music for everyday listening | 192 kbps | 86 MB |
| Music for good headphones | 256–320 kbps | 115–144 MB |
The uncompressed hour, for comparison, is roughly 635 MB at CD quality. Whatever you choose, keep the original WAV if it is a master recording: MP3 encoding cannot be undone.
How the encoder works
Tinyvert uses LAME, the encoder behind Audacity's MP3 export and most desktop tools, compiled to WebAssembly so it runs inside the browser. The 300 KB module is fetched the first time you convert and cached afterwards. The WAV is read as PCM, which needs no decoding, and encoded at the bitrate you chose with the sample rate and channel count untouched. A typical song takes a few seconds; a two-hour recording takes correspondingly longer, with the progress bar showing how far along it is. Title and artist tags are rare in WAV files, but any that exist are written into the MP3.
Recordings stay on your device
Raw recordings are often confidential: interviews, therapy sessions, unreleased tracks, legal dictation. Nothing here is uploaded. The file is read into memory, encoded and offered back for download, and the page works offline after its first use. The same design means large files are limited by your device's memory, so a very long WAV is best converted on a desktop or laptop rather than a phone.
See also
For the reverse trip, MP3 to WAV decodes a file back to PCM for editing. If you want smaller files without any loss, WAV to FLAC typically halves the size and converts back bit-for-bit. Compress Audio does the same job as this page with a 96 kbps default aimed at speech. The background is in MP3 vs WAV vs FLAC.