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Your files are never uploaded. Everything is processed in your browser and nothing is stored.

Subtitle Converter (SRT, VTT, SMI)

Convert subtitles between SRT, WebVTT and SMI, and move the timing earlier or later when the captions are out of sync with the video. Old files saved in legacy encodings are detected and read correctly. Everything runs in your browser, so your subtitles are never uploaded.

Or paste subtitle text

Pasted text is converted only when no file is chosen.

Convert to
Timing shift
sec

Decimals are fine, such as 0.5 or 1.25 seconds (millisecond precision).

Encoding and SMI options

Choose a subtitle file, pick the output format and timing, then press Convert.

Converted
    Preview: 
    
      
    
    
    
  
    

    


    
  
    How to use the subtitle converter
    
  
      
    
    1. Press Choose subtitle files and pick .srt, .vtt or .smi files. Choose several at once to convert them all with the same settings and download a ZIP.
      2. 
    
    2. Pick the output format. YouTube and web players take VTT, almost every desktop player and editor takes SRT, and SMI is the old SAMI format used by some Windows players.
      Text drops the timestamps and gives you the dialogue one line per cue, handy for a transcript.
      3. 
    
    3. If the subtitles are early or late by the same amount all the way through, set a timing shift. If they start in sync and drift further apart, use the frame rate fix.
      4. 
    
    4. Press Convert subtitles to get a preview and download buttons. When you only change the timing, the new file gets a _sync suffix so it is not confused with the original.
      5. 
  
    

    


    
  
    SRT vs VTT vs SMI
    
  
    
    
    
      
    FeatureSRTVTT (WebVTT)SMI (SAMI)
    
      
        
    Timestamp00:00:01,000 (comma)00:00:01.000 (period)Start=1000 (milliseconds)
    
        
    Used byMost players and video editorsYouTube, HTML5 <video>, e-learning platformsOlder Windows players, Korean fansubs
    
        
    LanguagesOne per fileOne per fileSeveral per file (classes)
    
        
    Styling<i>, <b>, <u>Position and style settingsHTML fonts and colors
    
          
    
    
  
    
  
    The converter keeps the dialogue, the timing and italic, bold and underline. Format-specific extras such as VTT cue positions or SMI font colors have no equivalent in the other formats and are dropped.
    VTT voice tags (<v Name>) become "Name: line" so you still know who is speaking.
    

    


    
  
    Fixing out-of-sync subtitles
    
  
  
    Cues pushed before 0:00 by an advance are removed, and a cue that straddles 0:00 is trimmed to start at zero.
    

    


    
  
    Garbled characters in old subtitle files
    
  
    Subtitles made before UTF-8 became the norm were often saved in a legacy code page, and smart TVs, phones and YouTube then show the accented or Korean letters as junk such as "é" or "¾È³ç".
    The converter checks the bytes for a byte-order mark, valid UTF-8 or legacy Korean EUC-KR and reads the file accordingly; the output is always UTF-8, which every modern player understands.
    If detection guesses wrong, set the source encoding under Encoding and SMI options. For text that was already copied in garbled form, try the mojibake fixer.
    

    


    
  
    FAQ
    
  
    Are my subtitle files uploaded?
    
  
    No. The files are read and converted entirely in this browser and are never sent to or stored on a server, so unreleased translations stay private.
    
  
    Which format should I upload to YouTube?
    
  
    YouTube accepts both SRT and VTT but not SMI, so convert SMI files first. For the <track> element of an HTML5 <video>, only VTT works.
    
  
    My SMI file has two languages.
    
  
    When you choose an SMI file, the languages inside it (for example KRCC and ENCC) appear under Encoding and SMI options → SMI language. Pick one before converting; otherwise the first language is used.
    
  
    Can I burn the subtitles into the video?
    
  
    This tool works on subtitle files only. Most players load a subtitle automatically when it sits next to the video with the same name (movie.mp4 and movie.srt).
    If you trimmed the start of a video with Split & Trim Video, advance the subtitles by the amount you cut.
    

    

    
  
    Sources
    
  

    

    
    




    
    


    
  
  

    



    
    


    
    
    
    


    
  
  
    
    
    
    
      

  
    
    
    
      
      
    Split & Trim Video
    
      
    
    
    
    Split an MP4 or AVI into equal parts, cut it at chosen times or trim out one clip, without quality loss. Processed in your browser, never sent to a server.
    
    No upload · runs in your browser
  
    
    

    
    
    
    
    
      

  
    
    
    
      
      
    Merge Videos
    
      
    
    
    
    Join MP4, AVI and MOV videos into one in the order you choose, without re-encoding when they match. Processed in your browser, never sent to a server.
    
    No upload · runs in your browser
  
    
    

    
    
    
    
    
      

  
    
    
    
      
      
    Fix Garbled Text (Mojibake)
    
      
    
    
    
    Repair mojibake like ’ or é caused by wrong character encodings, and normalize decomposed Unicode. Runs in your browser; nothing is sent to a server.
    
    No upload · runs in your browser
  
    
    

    
    
    
    
    
      

  
    
    
    
      
      
    Merge MP3
    
      
    
    
    
    Join several MP3 files into one in the order you choose, without quality loss when they share a format. Processed in your browser, never sent to a server.
    
    No upload · runs in your browser