Free online RAR to WEBM converter

A RAR file is an archive, so a program or device cannot normally play it as WEBM until its contents are extracted. This conversion is needed when a video packed in RAR must be edited, shared, or played in a browser or media player that supports WEBM.

What the RAR format is

RAR is a compressed archive format created primarily by WinRAR and also produced by compatible tools such as 7-Zip. It can contain one or more video files, along with subtitles, metadata, documents, or other archives. RAR files commonly appear as downloaded software packages, backups, and split archives named archive.part1.rar, archive.part2.rar, and so on.

RAR compression does not define the video format inside the archive. A RAR may contain MP4, MKV, AVI, or another media file, and the archive itself cannot be transcoded into WEBM without first extracting that source file.

What the WEBM format is

WEBM is a multimedia container designed mainly for web playback. It commonly stores VP8, VP9, or AV1 video with Vorbis or Opus audio. Browsers, HTML5 video players, and many modern media applications support WEBM without additional codecs.

WEBM can provide smaller files than an uncompressed source, especially with VP9 or AV1, but conversion is lossy when the selected codecs use lossy compression. It is suitable when browser compatibility, streaming, or a relatively compact video file matters more than preserving the original container and codecs.

How to actually convert RAR to WEBM

1. Extract the RAR archive

Install a desktop archive utility such as 7-Zip or WinRAR, then choose Extract here or Extract to…. With 7-Zip on the command line, use:

7z x archive.rar -oextracted

For a split archive, keep every part in the same folder and open archive.part1.rar; the extractor reads the remaining parts automatically. Enter the archive password if it is encrypted. After extraction, identify the actual video file, for example video.mp4 or source.mkv.

2. Transcode the extracted video with FFmpeg

FFmpeg is suitable for Windows, macOS, and Linux. A broadly compatible VP9 and Opus conversion is:

ffmpeg -i source.mp4 -c:v libvpx-vp9 -crf 32 -b:v 0 -c:a libopus -b:a 128k output.webm

Replace source.mp4 with the extracted filename. Lower VP9 CRF values improve quality and increase size; values around 30–36 are common starting points. Use -crf 28 for higher quality or -crf 36 for a smaller file.

For faster encoding with a size target, specify a video bitrate instead:

ffmpeg -i source.mkv -c:v libvpx-vp9 -b:v 2M -c:a libopus -b:a 128k output.webm

If the source already uses browser-compatible codecs, remuxing may avoid re-encoding:

ffmpeg -i source.mkv -c copy output.webm

This copy command works only when the source codecs and streams are valid for WEBM. If FFmpeg reports an incompatible codec, use the transcoding command instead.

Using the built-in online converter

You can convert the file on 101convert.com for free without installing software. Upload the RAR archive, select WEBM as the output when the service supports the archive’s contents, start the conversion, and download the result. Password-protected or multipart archives may require extraction with a desktop utility first.

Quality, compatibility, and limitations

• Extracting a RAR does not reduce video quality; transcoding to VP9, AV1, or another lossy codec can.
• WEBM supports specific stream types. A source containing unsupported video, audio, subtitle, or attachment streams may need selective conversion or removal.
• Use -an to remove audio, or specify a compatible audio stream with -map 0:v:0 -map 0:a:0 when the source contains multiple streams.
• WEBM is less suitable when you need broad support in older TVs, editing applications, or legacy mobile players. MP4 with H.264 and AAC is often more compatible outside modern browsers.
• RAR recovery records, encryption, and split volumes affect extraction, not the WEBM encoding settings. A damaged or incomplete archive must be repaired or reacquired before conversion.