Free tool
WAV to M4A converter
Drop a WAV here to convert WAV to M4A in your browser: the uncompressed recording becomes AAC at 96, 128 or 192 kbps, 7 to 19 times smaller, ready to send or to play on an iPhone, and nothing is uploaded.
- Free
- Works on phones
- Nothing is uploaded
Save as
M4A quality
AAC sound in an M4A file, for Apple devices and apps. AAC sound, such as a video’s, is copied as is; other sound is encoded at the quality you pick.
Drop your WAV file here, or Choose your WAV file
Any audio or video file, up to 1 GB and 2 hours. It’s converted in your browser; nothing is uploaded.
MP3 encoding by LAME, open-source software.
Shrinking an interview so you can share it? NoteOwl imports the WAV or the M4A and transcribes it on your Mac, with each voice labelled and the text searchable.
How it works
How do you convert a WAV file to M4A?
Choose a bitrate and drop the WAV. A WAV is already raw samples, so the page passes them to your browser’s own AAC encoder, which packs them into an .m4a file. A five-minute stereo WAV took 1.9 to 2.4 seconds in Chrome.
- 1
Pick 96, 128 or 192 kbps
192 for music and finished mixes, 128 for interviews and podcasts, 96 when the smallest file matters most.
- 2
Add the WAV
16-bit, 24-bit or 32-bit float, mono or stereo. A recording with more than two channels is mixed down to stereo.
- 3
Save the M4A
Play it, then download. Title and artist from the WAV’s INFO tags are carried into the M4A.
How much smaller is an M4A than the WAV?
Between 7 and 19 times, depending on the bitrate and the browser. A five-minute, 52.9 MB CD-quality WAV came out at 2.74 to 5.35 MB in Chrome and 3.66 to 7.26 MB in Safari’s engine, which writes the full bitrate you ask for.
- M4A, 96 kbps
- Size in Chrome2.74 MB (19× smaller)
- Size in WebKit3.66 MB (14× smaller)
- Time, Chrome / WebKit1.9 s / 2.6 s
- M4A, 128 kbps
- Size in Chrome3.56 MB (15× smaller)
- Size in WebKit4.86 MB (11× smaller)
- Time, Chrome / WebKit2.2 s / 3.1 s
- M4A, 192 kbps
- Size in Chrome5.35 MB (10× smaller)
- Size in WebKit7.26 MB (7× smaller)
- Time, Chrome / WebKit2.4 s / 3.2 s
- MP3, 192 kbps, for comparison
- Size in Chrome7.2 MB (7× smaller)
- Size in WebKit7.2 MB (7× smaller)
- Time, Chrome / WebKit2.6 s / 3.0 s
| Saved as | Size in Chrome | Size in WebKit | Time, Chrome / WebKit |
|---|---|---|---|
| M4A, 96 kbps | 2.74 MB (19× smaller) | 3.66 MB (14× smaller) | 1.9 s / 2.6 s |
| M4A, 128 kbps | 3.56 MB (15× smaller) | 4.86 MB (11× smaller) | 2.2 s / 3.1 s |
| M4A, 192 kbps | 5.35 MB (10× smaller) | 7.26 MB (7× smaller) | 2.4 s / 3.2 s |
| MP3, 192 kbps, for comparison | 7.2 MB (7× smaller) | 7.2 MB (7× smaller) | 2.6 s / 3.0 s |
Why shrink a WAV recording into an M4A?
File size, mostly. A WAV keeps every sample uncompressed, 10.6 MB a minute at CD quality, so a half-hour interview passes 300 MB. AAC cuts that by 7 to 19 times, which makes a recording far easier to email, message or keep on a phone.
The WAVs worth shrinking are usually finished ones: interviews and voice-overs from a field recorder, GarageBand or Logic bounces you want on a phone, and recordings an app or a form wants as M4A. Keep the WAV itself if you will edit it again, since each AAC encode drops a little detail.
Should a WAV become an M4A or an MP3?
M4A for Apple devices and apps, and when the smallest file matters: AAC generally holds up better than MP3 at the same bitrate. MP3 for the widest reach: car stereos, older players and sites that list .mp3 as the only format they take.
Choose MP3 in the converter above, or open the WAV to MP3 converter. At 192 kbps the same five-minute WAV became 7.2 MB, identical in every browser because the MP3 is constant bitrate.
Does a 48 kHz WAV stay at 48 kHz?
Yes. A 48 kHz WAV, the usual rate for video and many recorders, becomes a 48 kHz M4A, and a CD-rate WAV stays at 44.1 kHz. Lower rates such as 22.05 or 32 kHz come out at 44.1 kHz, the lower of the two rates Chrome’s AAC encoder accepts.
Bit depth needs no preparing either: a 24-bit or 32-bit float WAV converts directly, with no need to make a 16-bit copy first.
Can iTunes or the Music app do this instead?
For songs already in your library, yes. On a Mac, the Music app’s File → Convert → Create AAC Version makes an M4A copy, and iTunes on Windows has the same command. This page suits a single recording you would rather not add to a library.
Can NoteOwl transcribe the WAV without shrinking it?
Yes. NoteOwl imports WAV recordings as they are, and M4A ones too, then transcribes them on your Mac with on-device AI models and labels each speaker. Shrink a WAV here to share or store it; for NoteOwl either file works.
The transcript can leave as Markdown, PDF or text through export, or as SRT subtitles for a video.
FAQ
Questions about shrinking WAV files to M4A
Is the WAV uploaded while it converts?
No. The WAV is read from your device and encoded by your browser’s own AAC encoder, so nothing is uploaded. A large recording converts as privately as a small one, with no transfer to wait for.
Does converting WAV to M4A lose quality?
A little: AAC is lossy, so it drops detail the ear is least likely to miss. 192 kbps keeps the most, and 96 kbps is better suited to speech than to music. Keep the WAV if you may edit the recording again.
Why is the Chrome M4A smaller than the Safari one?
The browsers use different AAC encoders. Safari’s writes the bitrate you choose, 7.26 MB for five minutes at 192 kbps; Chrome’s saves bits on easy material and wrote 5.35 MB. Both are ordinary AAC-LC M4A files.
Can it read compressed or unusual WAV files?
Yes. Besides 16 and 24-bit PCM it reads 8-bit, 32-bit integer and float, μ-law, A-law, and IMA or Microsoft ADPCM, the 4-bit kind some voice recorders make. Any of them can become an M4A.
Does the M4A keep my WAV’s title and artist?
Yes, when the WAV has them: a title and artist in its INFO chunk are copied into the M4A’s tags. If the WAV has none, the M4A simply takes its file name, ending in .m4a.
How long a WAV can it take?
The limit is 1 GB or 2 hours, whichever comes first. A 44.1 kHz stereo WAV reaches 1 GB at about 101 minutes, so long stereo recordings meet the size limit before the time limit.
Keep exploring
More audio converters
- Audio converterConvert audio and video files to MP3, WAV, M4A or OGG in your browser: M4A, FLAC, AIFF, OGG, Opus, WebM, MP4 and MOV in; nothing is uploaded
- MP3 converterConvert any audio or video file to MP3 in your browser, from WAV, M4A, FLAC, OGG and AIFF to MP4, MOV and WebM videos; nothing is uploaded
- WAV converterConvert any audio or video file to a 16-bit WAV in your browser, or a WAV to MP3, M4A or OGG; nothing is uploaded
- M4A converterConvert audio and video to M4A in your browser (AAC sound copied without re-encoding), or an M4A to MP3, WAV or OGG; nothing is uploaded
Related
- WAV to MP3 converterConvert WAV to MP3 in your browser, 16-bit to 32-bit float at any sample rate, and see how much smaller the MP3 is; nothing is uploaded
- MP3 to M4A converterConvert MP3 to M4A (AAC) in your browser at 96, 128 or 192 kbps, for iPhone, iPad and Mac apps; nothing is uploaded
- Export your notesExport meetings, dictations and notes as Markdown or PDF, imported transcripts as text or SRT, or everything as plain files; nothing is locked in
Interviews into searchable notes, on your Mac
Free to download. Runs entirely on your Mac.
macOS 26 or later · Apple Silicon (M1 or newer) · 16 GB memory minimum, 24 GB recommended
About NoteOwl
NoteOwl is private AI meeting notes and memory for the Mac. It captures meetings without a bot joining the call, labels every speaker, writes summaries and action items, and builds a memory of every conversation that you can chat with — fully offline, because the speech recognition and the AI run on the Mac itself. Dictation into any app is free; Pro is a one-time purchase.
NoteOwl pricing: what’s free and what Pro adds
Last updated