Free Subtitle Converter

Convert between SRT, VTT, SSA/ASS, SBV, TXT, and JSON subtitle formats instantly. 100% client-side -- your files never leave your browser.

Drop your subtitle file here or click to browse

SRT, VTT, ASS, SSA, SBV, TXT, JSON

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About Subtitle Formats

        

          

            

              
SRT (SubRip)

              
The most widely used subtitle format. Compatible with virtually all media players and video platforms. Uses comma-separated milliseconds (HH:MM:SS,mmm).

            

          

          

            

              
VTT (WebVTT)

              
Web Video Text Tracks format. Designed for HTML5 video and supported by all modern browsers. Uses dot-separated milliseconds (HH:MM:SS.mmm).

            

          

          

            

              
ASS / SSA (SubStation Alpha)

              
Supports rich styling, positioning, karaoke effects, and advanced typography. Popular in anime fansubs and complex subtitle productions.

            

          

          

            

              
SBV (YouTube SubViewer)

              
SubViewer format used natively by YouTube. Simple timestamp format ideal for video platform uploads and basic captioning.

            

          

        


        
How to Convert Subtitles

        

          

            

              
1

              
Upload or Paste

              
Drop your subtitle file or paste its content directly into the editor.

            

          

          

            

              
2

              
Choose Output Format

              
The input format is auto-detected. Select your desired output format from the dropdown.

            

          

          

            

              
3

              
Convert & Download

              
Click Convert to see the preview, then download the file or copy to clipboard.

            

          

        

      

    

  







    

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Frequently Asked Questions


        

        

            

                

                
Upload your audio or video file to STT.ai. Select your preferred AI model and options, then click Transcribe. Your transcript will be ready in minutes. Export as TXT, SRT, VTT, DOCX, JSON, or PDF.

            

            

                

                
Yes! STT.ai offers 600 free minutes per month for all users. No signup required for your first transcription. Paid plans with more minutes and features start at $5/month.

            

            

                

                
Accuracy depends on the AI model you choose and audio quality. Our best models achieve a 5-7% Word Error Rate on benchmarks, meaning 93-95%+ accuracy. Clear audio with minimal background noise produces the best results.

            

            

                

                
STT.ai offers 10+ models including Whisper Large V3, NVIDIA Canary, and more. You can compare results from different models on the same file.

            

            

                

                
Yes. After transcribing, export your transcript as SRT or VTT subtitle files. These work with YouTube, Vimeo, and all major video platforms.

            

            

                

                
Yes. STT.ai automatically identifies and labels different speakers using AI speaker diarization. Works across all models and languages.

            

            

                

                
Most files are transcribed in under 5 minutes. A 1-hour audio file typically takes 2-3 minutes with our fastest models.

            

            

                

                
STT.ai supports 20+ audio and video formats including MP3, WAV, M4A, FLAC, OGG, MP4, MKV, MOV, WebM, and AVI. Export as TXT, SRT, VTT, DOCX, JSON, or PDF.

            

            

                

                
Yes. Audio files are processed and deleted after transcription. Your data is never used for training. Client-side encryption is free on all plans — it encrypts stored transcripts with a key only you have. During processing, the server handles your audio in plaintext. Learn about our security.

            

            

                

                
Yes. STT.ai offers a REST API with Python and Node.js SDKs. Free tier includes 100 minutes/month.

            

            

                

                
Yes. STT.ai includes a built-in transcript editor where you can correct errors, rename speakers, and adjust timestamps.

            

            

                

                
Every transcript gets a unique shareable link. Export to DOCX or PDF for email. Pro plans offer password-protected and permanent links.