No upload · No account · No server
Subtitle tools that never see your files
Convert between SRT, WebVTT, ASS, SSA, SBV, TTML and more, retime and clean up the text, check it for accessibility — or start from video, bitmap subtitles and audio, with track extraction, OCR, speech recognition and narration running on this device. Everything happens in this browser tab, so your files never leave your machine.
Sample subtitles — processed the way this site processes yours: in the page, never on a server.
Why this one is different
Your files stay on your device
Every other subtitle converter has to upload your file, because the conversion happens on their server. This one does not need a server at all — parsing, conversion and writing all happen in the page you are looking at, even when the input is a video, a bitmap or an audio track.
You are told what gets dropped
Converting ASS to SRT throws away styling, positioning and karaoke timing. Most tools convert first and let you discover that afterwards. Every conversion page here lists what it will lose before you run it.
Every conversion is a page, not a mode
Each source and target format pair is its own page with its own loss report, worked examples and answers to the questions that pair actually raises — instead of one generic converter with two dropdowns.
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Eight families of subtitle work, from format conversion and accessibility compliance to video, bitmap subtitles and audio.
- Format conversionMove subtitles between SRT, WebVTT, ASS, SSA, SBV, SMI, LRC, MicroDVD, TTML, JSON, plain text and CSV — and see what each conversion drops before it runs.
- TimingShift, scale, re-frame and re-align subtitle timing: frame-rate conversion, overlap and gap repair, trimming to a range and splitting a file into parts.
- Text and stylingChange case, strip tags and SDH descriptions, recolour or reposition lines, merge or split bilingual tracks, find and replace, rewrap lines, fix encoding.
- Quality checksDetect structural subtitle defects: overlaps, gaps, empty cues, non-monotonic timing and unusual cue durations — one page per problem or all at once.
- Accessibility complianceCheck subtitles against reading speed, line length and display-duration thresholds from EN 301 549, WCAG 1.2.2, FCC, Ofcom, Netflix and BBC rules.
- TimecodeRe-label subtitle timecodes between 30 fps non-drop and 29.97 drop-frame, two conventions that drift 3.6 seconds apart every hour, in both directions.
- Export and integrationTurn subtitles into an HTML track element, a YouTube chapter list, a plain text transcript or a printable PDF — outputs no subtitle format can carry.
- Media inputExtract subtitle tracks from video, transcribe speech with Whisper, OCR PGS and VobSub bitmaps, voice subtitles and resync audio — all inside your browser.