Top Free Tools to Convert Subs to SRT

Converting subtitle files to SubRip (SRT)—the most universally accepted format—depends entirely on whether your source file is text-based (like VTT or ASS) or image-based (like SUB/IDX or SUP from DVDs/Blu-rays). 🌐 Best Free Online Text-Based Converters

If you already have a text subtitle file (like .vtt, .ass, or .ssa) and just need to quickly convert it into an .srt format, these browser-based tools require zero installation:

⁠GoTranscript Subtitle Converter: Completely free online platform with no registration required. It allows you to drag-and-drop text-based files (including alternative .sub text variations) and convert them to SRT in seconds.

⁠Subtitle Tools Converter: A web app specifically designed to strip away heavy styling, fonts, and karaoke effects from advanced formats like Advanced Substation Alpha (.ass / .ssa) and turn them into clean, basic SRT text.

⁠HappyScribe Subtitle Converter: An intuitive, free browser tool that supports straightforward conversions between VTT and SRT. It caps file sizes at 2MB for the free tier.

🛠️ Best Free Software for Image-Based Subtitles (SUB/IDX to SRT)

If your .sub file is paired with an .idx file (VobSub format), it doesn’t contain text—it contains bitmap images of text extracted from a disc. To convert these into editable text SRTs, you must use Optical Character Recognition (OCR):

Subtitle Edit: The absolute gold standard for open-source desktop software (Windows/Linux). It features a powerful, built-in OCR system that scans image-based subtitles, allowing you to fine-tune the dictionary and spacing “fuzziness” to convert tricky images into pristine text SRT files.

⁠SubExtractor (Online SUB/IDX to SRT): If you do not want to install software, this web tool handles the heavy lifting on its own servers. You upload both the .sub and .idx files, choose your language, and its cloud OCR engine parses the data into a downloadable SRT over 5 to 15 minutes.

🤖 Best Free AI Tools to Generate SRTs Directly From Video/Audio

If your “subs” are currently embedded or burned into a video file and you need to extract or generate fresh SRT timecodes entirely from scratch, use these automated AI transcription tools: Reddit·r/PleX