Free online WEBM to 3GP converter

Older mobile phones, MMS workflows, and legacy playback programs may accept 3GP but reject WEBM. Converting the file can also reduce its resolution, bitrate, and storage size for hardware with limited processing power or memory.

What the WEBM format is

WEBM is an open multimedia container designed primarily for web video. It commonly contains VP8, VP9, or AV1 video and Vorbis or Opus audio; current versions of Chrome, Firefox, Edge, and other browsers support these combinations natively.

WEBM files are commonly created by browser-based screen recorders, OBS Studio, and other capture or streaming applications. Its codecs are efficient for web delivery, but older phones, media players, and editing programs may not support them.

What the 3GP format is

3GP is a multimedia container specified by the 3rd Generation Partnership Project for mobile-network services and older mobile phones. Common combinations include H.263 or MPEG-4 Part 2 video with AMR-NB or AAC audio.

3GP targets small files and modest hardware, so its typical profiles use low resolutions and bitrates. It remains useful when a legacy phone, MMS workflow, embedded device, or older application specifically requires it; MP4 is usually more compatible with modern phones and computers.

Convert without installing software

1. Open the WEBM-to-3GP converter on 101convert.com.
2. Upload the source .webm file and choose 3GP as the output format.
3. Start the conversion and download the resulting .3gp file when processing finishes.

If the converter provides encoding controls, use a frame size such as 176×144 or 320×240, approximately 15 frames per second, and a conservative bitrate for a very old phone. Uploading requires sending the source file to the service, so use desktop conversion instead for files that must remain local.

Convert with FFmpeg

FFmpeg is suitable for repeatable local conversions and exposes the codec, frame size, frame rate, and bitrate settings directly. This command creates a compact 3GP file using MPEG-4 Part 2 video and AAC audio:

ffmpeg -i input.webm -vf "scale=320:240:force_original_aspect_ratio=decrease,pad=320:240:(ow-iw)/2:(oh-ih)/2" -r 15 -c:v mpeg4 -vtag mp4v -b:v 350k -c:a aac -ar 8000 -ac 1 -b:a 32k -f 3gp output.3gp

Replace input.webm with the source filename. The scale-and-pad filter preserves the aspect ratio and fits the video inside 320×240; smaller dimensions and lower bitrates reduce size further. The output is re-encoded rather than merely renamed.

Some particularly old devices require H.263 video and AMR-NB audio. If the installed FFmpeg build includes the AMR-NB encoder, use a device-specific command such as:

ffmpeg -i input.webm -vf "scale=176:144" -r 15 -c:v h263 -b:v 192k -c:a libopencore_amrnb -ar 8000 -ac 1 -b:a 12.2k -f 3gp output.3gp

If FFmpeg reports that libopencore_amrnb is unavailable, install a build that includes that encoder or use the MPEG-4/AAC command. Encoder availability varies between operating-system packages and FFmpeg builds.

Quality and compatibility limits

Changing the container does not preserve incompatible codecs. The video and audio usually must be decoded and re-encoded, which can reduce sharpness and introduce compression artifacts. Lowering resolution or bitrate reduces detail and increasing those values cannot restore detail missing from the WEBM source.

A .3gp extension alone does not guarantee playback. The target device may require a specific combination of H.263, MPEG-4 Part 2, AMR-NB, or AAC, as well as limits on resolution, frame rate, audio channels, sample rate, and bitrate. Older phones often work best with 176×144 video, 15 fps, mono 8 kHz audio, and conservative bitrates.

Test a short converted file on the actual device before processing a large collection. If the file plays without sound, stutters, or is rejected, change the codec combination and reduce the frame size, frame rate, or bitrate rather than changing only the filename extension.