ASS (Advanced SubStation Alpha) is the subtitle format for people who care where the text sits: styles, positioning, fonts, karaoke timing. Anime fansubs made it standard. Converting it to a plain format means the words survive and the choreography does not.
Every conversion below runs in this page, on your own machine. Nothing is uploaded, there is no queue, and there is no account to make. Pick a target format, or just drop an ASS file above and choose afterwards.