Convert WAV to MP3 on iPhone: Steps and File Sizes

Example: a band rehearsal WAV, 3 minutes 30 seconds, recorded on a field recorder at 48 kHz and 24 bits and copied to the iPhone over USB-C. A file like that is too big to send in Messages and gets refused by many upload forms. Here's how the sizes come out:

One 3:30 recording (210 seconds), original WAV vs. MP3 from the app
File	Size	Free or Pro
Original WAV, 48 kHz 24-bit stereo	60.48 MB	-
Same length as a 44.1 kHz 16-bit WAV	37.04 MB	-
MP3 64 kbps	1.68 MB	Free
MP3 128 kbps	3.36 MB	Free
MP3 192 kbps	5.04 MB	Pro
MP3 320 kbps	8.40 MB	Pro

A WAV's size is sample rate times bytes per sample times channels times seconds: 48,000 × 3 × 2 × 210 = 60,480,000 bytes. An MP3 here is constant bitrate, so 128 kbps is 16,000 bytes a second whatever the WAV was. That's 18 times smaller for this file.

The steps

Get the WAV into Files first: AirDrop it, save the email attachment, or copy it from a recorder or USB drive.
In the app, open the Videos tab and tap + at the top right. Pick the WAV.
The editor opens on the waveform. Trim with Start and End if there's a count-in or silence to cut.
Select format is already on MP3. Under Quality, pick 64 kbps or 128 kbps.
Name it in Audio title (it starts as the WAV's file name) and tap Convert to Audio.
When the file opens, use the top buttons to share it or save a copy back to Files.

On the free tier, tapping 192, 256 or 320 kbps shows a lock, opens the Pro screen and puts the picker back on 128. It's easy to miss the little padlock at first.

Which bitrate to pick

For a rehearsal you want to share with the band, 128 kbps: most listeners can't tell it apart from the WAV on a quick switch on headphones. For a podcast or a lecture, 64 kbps. For a mix someone will judge closely, keep the WAV or go 320 with Pro, and accept a file two and a half times the size of 128.

What you lose going from WAV to MP3

Some detail, by design. One thing worth knowing: the app turns the WAV into an AAC (M4A) copy first, then builds the MP3 from that copy, so you're compressing twice, not once. You won't hear it at 128 kbps on a rehearsal, but if quality matters most, choose M4A under Select format instead; it's the least processed output here and plays on every Apple device.

One WAV at a time. Batch conversion only takes videos from Photos, not files from Files.
3 conversions a day on the free tier, with ads. Pro removes the cap and the ads.
No sample rate or mono option for MP3; you choose the bitrate and nothing else.
MP3 tags (title, artist) can't be edited afterwards in the app. Type the name you want in Audio title before converting.
Converting back to WAV later won't restore what the MP3 dropped. Keep the original WAV somewhere.

Questions and answers

Can you convert WAV to MP3 on iPhone for free?

Yes. The free tier converts 3 files a day to MP3 at 64 or 128 kbps, on the phone, with ads. Higher bitrates and unlimited conversions need Pro.

Can I trim a WAV file on iPhone before converting it?

Yes. When you open the WAV through +, the editor shows the waveform with Start and End handles. Only the part between them goes into the MP3.

Does iPhone play WAV files without converting?

Yes, the Files app plays WAV on its own. Converting matters when a website, email limit or another device wants MP3, or the file is too big to send.

Is 128 kbps good enough for music?

For sharing and casual listening, yes; 3:30 of music comes out at 3.36 MB. If someone will mix or master from it, send the WAV instead of any MP3.

128 vs 320 kbps: which MP3 bitrate to choose, and how big the file will be · MyMP3 Converter
How do you trim or cut an audio file on iPhone? · MyMP3 Converter

How do you convert WAV to MP3 on iPhone?