Private browser-based audio compression

Compress Audio on iPhone

Compress audio on iPhone in Safari or another modern browser, with settings for Voice Memos and shareable MP3 copies.

Your audio is compressed locally in your browser. Files are not uploaded to a server.
MP3 / WAV / M4A / AAC / OGG / FLAC inputMP3M4A / AACOGG
File-
Size-
Duration-
Your audio is compressed locally in your browser. Files are not uploaded to a server.
Compression mode
Advanced settings
Select an audio file to begin.

Compression result

Original size-
Compressed size-
Saved-
Output-
Bitrate-
Download compressed audio

Practical focus

Use this page to compress iPhone recordings, Voice Memos, and mobile M4A files without installing an iOS app.

Quick tips

  • iPhone recordings are often M4A.
  • MP3 output improves compatibility.
  • Long voice memos usually work well as mono at 64-96 kbps.

How to use

  • Open the page on iPhone and use the file picker to select an audio recording or a file from Files.
  • For Voice Memos, choose mono and 64-96 kbps.
  • Export MP3 if the file is going to WhatsApp, email, or a web form.
  • Expect long recordings to take longer on a phone than on a desktop browser.

Recommended settings

iPhone audioSuggested setting
Voice MemoMP3/M4A, mono, 64-96 kbps
Lecture recordingMP3, mono, 64 kbps
Music clipAAC or MP3, stereo, 128-192 kbps
Sharing to chatMP3, Target 10MB or 16MB

Supported formats

M4A, MP3, and WAV are common iPhone sources.

MP3 output is easiest for sharing outside the Apple ecosystem; M4A/AAC is efficient for mobile playback.

Quality vs file size

iPhone voice recordings are already compressed, but long duration can still make them large.

Mono and lower bitrate work well for speech. Music clips should keep stereo and a higher bitrate.

Privacy and local processing

Compression runs in your browser, so the original audio is not uploaded to a server.

Large files can still be slow because decoding and encoding use your device memory and CPU.

Things to watch

  • This is not an iOS app download; it runs in the browser.
  • Very large recordings can be slow on older iPhones.

FAQ

Can I compress audio on iPhone without an app?

Yes. Use Safari or another modern browser and select the file from Files or a recording source.

Why are iPhone recordings often M4A?

Apple commonly stores voice recordings in M4A with AAC for efficient mobile audio.

Should I convert iPhone M4A to MP3?

Use MP3 when compatibility with other apps or recipients matters.

What settings are best for voice memos?

Mono at 64-96 kbps is a practical range.

Why is compression slower on my phone?

The browser uses the phone CPU and memory to decode and encode the file locally.