Files never leave your device. Any size, any length.
3GP to MP3.
No size, no length limits.
Old phone recordings; AMR voice inside needs the cloud, AAC converts on-device.
Files never leave your device. Any size, any length.
Old phone recordings; AMR voice inside needs the cloud, AAC converts on-device.
Device or cloud
3GP mobile video files (3GPP (ISOBMFF)) usually carry AAC, AMR audio and come from feature phones, early Android. Old phone recordings; AMR voice inside needs the cloud, AAC converts on-device.
Is my 3GP file uploaded?
Usually not — most 3GP files convert on your device.
Is there a file size or duration limit?
No. mp3fy streams the file while converting, so a 20 GB recording or a 10‑hour lecture works the same as a short clip.
What bitrate should I pick?
192 kbps is the sweet spot for music and speech; 128 kbps for voice notes and podcasts; 320 kbps if you want the maximum. You can also keep stereo or down‑mix to mono.
Are my tags and cover art kept?
Yes — title, artist, album and embedded cover art are carried over into the MP3 when the source has them.