It is the main tool used for fansubbing, the practice of creating or translating unofficial subtitles for visual media by fans.

Aegisub's design emphasizes timing, styling of subtitles, and the creation of karaoke videos.

Aegisub can export subtitles to other common formats as well, such as SubRip's ".srt" format,[5] but at the cost of losing all other features except for raw text and basic timing.

In fansubbing, Aegisub is used when translating and interpreting languages, creating and adjusting timing, editing subtitles, typesetting, quality checking, karaoke lyric timing and karaoke text effects.

However, different tools can be used to achieve the same effect, such as Adobe Premiere Pro for typesetting,[6] or a simple text editor like Notepad++ when providing translated text.