Upload a WAV file and get a M4A back. No signup, no watermark, no limit on how many.
WAV is raw, uncompressed PCM in a Microsoft container: the audio exactly as it was sampled, with nothing clever done to it.
Where you run into it: Recording sessions, sample libraries, video editors, anything that has to be edited rather than merely listened to.
What it costs you: It is enormous — roughly 10 MB a minute in CD-quality stereo — and it carries almost no tagging, so a folder of WAVs is a folder of filenames.
M4A is an MPEG-4 container holding AAC audio — the same codec as a bare .aac file, wrapped so that players, tags and cover art all behave.
Where you run into it: iTunes and Apple Music purchases, voice memos, Zoom and Teams recordings, most phone-recorded audio.
What it costs you: Outside Apple's ecosystem support is good but not universal, and a few older tools still refuse the extension on sight.
Your WAV is encoded as AAC and wrapped in an MP4 container, which is what the .m4a extension means. Of the four lossy targets here this is the one that gives up least of what a session export might be carrying: a 96 kHz master stays at 96 kHz, and a 5.1 mix keeps all six channels. MP3 can do neither — it cannot carry a rate above 48 kHz, and it folds surround down to stereo — so if your WAV is anything other than ordinary CD-rate stereo, this is the conversion that respects it.
One thing this page cannot do, and it is worth saying plainly: it writes AAC, not Apple Lossless. If you wanted an .m4a that keeps your WAV intact — the ALAC case — this is not that conversion, and the file you get back will be lossy no matter which rate you choose. For a lossless destination that Apple software reads, convert to FLAC and import that, or keep the WAV. If lossy is what you wanted all along, this is the right target for Apple hardware, for a multichannel mix, and for anything above CD rate.
Yes, entirely, and there is no cap on how many files you convert. No account, no watermark, no trial.
Yes, and AAC is the most efficient of the four codecs on offer, so it gives up the least per kilobit. Best here is a flat 192 kbps rather than a variable setting, which from a lossless stereo source is comfortable and from a mono voice recording is frankly extravagant — at a fixed rate a quiet solo take pays exactly what a dense mix pays. Pick a lower number from the list if the file is speech and the size matters.
About a twelfth of the WAV, plus a few kilobytes for the container's index and tag space. Because the rate is fixed, the arithmetic is simple and honest: four minutes of stereo is close to 5.5 MB regardless of what the music is doing. Add artwork afterwards and the file grows by whatever the image weighs, which is usually more than the container itself.
Yes — M4A is one of the formats this converter writes, so the reverse page exists at /m4a-to-wav/. Be clear about what comes back, though: the WAV you get is a faithful copy of the M4A, not of the original. The loss happened on the way out, and returning to a lossless format stops further loss rather than undoing it. Keep the original WAV if you still have it.
The file is uploaded to do the conversion — nothing here runs in your browser — and both your upload and the converted result are deleted the moment the file is sent back. Nothing is stored and nothing is logged beyond the request itself.