Free subtitle tools
A full subtitle editor, a subtitle checker, a transcript cleaner and five single-purpose fixes, right in your browser: shift the whole file, shift part of it, clean up SDH/credits/ads, change the colour, change the position. Free to use, nothing uploaded is kept.
Subtitle Editor
Open an SRT, WebVTT or ASS file — or the subtitles inside an MKV, MP4, WebM or MOV video — and edit it line by line against the video: text, timing, split, merge, find & replace, clean up, reposition, italics and colour. Runs entirely in your browser — nothing is uploaded.
Subtitle Checker
Check a file for overlaps, flicker-short gaps, lines too long or too fast to read, empty and duplicate subtitles and broken tags — then fix them all and download.
Transcript Cleaner & Converter
Paste a Zoom, Teams or YouTube transcript and remove the timestamps, speaker labels, um and uh and sound tags — or turn a timestamped transcript into an SRT or WebVTT subtitle file.
Shift Timing
Move every subtitle in the file earlier or later by the same amount — the fix for a track that's consistently off.
Shift a Section
Move a range of subtitles — subtitles 340 to the end, say — without touching the rest of the file.
Cleanup
Strip SDH sound descriptions, credits, ads and speaker labels; fix mangled encoding, OCR misreads and overlapping timing.
Color
Set the colour of the subtitle text, or strip colouring the file already carries, in one pass.
Position
Move subtitles to another part of the frame — top, middle, or any corner on a 3×3 grid.
The AI Subtitle Studio desktop app has this same Tools section built in — plus AI transcription, translation and batch processing for a whole season at once, all running locally on your Mac or PC.
Convert a subtitle to another format
ASS/SSA (Advanced SubStation Alpha) → SRT (SubRip)
Turn a styled .ass or .ssa subtitle into plain SubRip — dialogue and exact timing kept, fonts, colors, positioning and karaoke stripped since SRT can't hold them.
ASS/SSA (Advanced SubStation Alpha) → WebVTT
Turn a styled fansub .ass file into standards-correct WebVTT for HTML5 video and web players — dialogue and timing kept, styling stripped.
MicroDVD (.sub) → SRT (SubRip)
MicroDVD times its cues in video frames, not seconds — pick the right frame rate and this converts it to a normal, time-based SRT.
MPL2 → SRT (SubRip)
MPL2 times its cues in tenths of a second — this converts that timing to SRT's format and keeps every line.
SAMI (.smi) → SRT (SubRip)
SAMI subtitles time each cue by when the next one starts, not by their own end time — this works that out and writes a normal SRT.
SBV (YouTube captions) → SRT (SubRip)
SBV is YouTube's original caption download format — convert it to a normal, numbered SRT that any player accepts.
SRT (SubRip) → Plain text
Strip cue numbers and timestamps from an SRT, WebVTT or ASS file, leaving just the dialogue as a readable transcript.
SRT (SubRip) → WebVTT
Turn a plain .srt file into WebVTT for HTML5 video, YouTube uploads or any platform that expects .vtt captions.
WebVTT → SRT (SubRip)
Turn a .vtt caption file into plain SubRip for players and editors that expect .srt — timing preserved exactly.
Open a file, choose what to change, download
Pick a tool
Each tool is its own page and changes exactly one property of the file — nothing else is touched.
Upload one file
SRT, WebVTT or ASS/SSA — character encoding and format are detected automatically.
Get it back, edited
The result downloads straight to your device. Nothing you upload is kept on our servers afterward.
These tools don't rewrite what they weren't asked to touch
A subtitle a tool doesn't change comes back exactly as it was — down to the way its timestamps were spelled. This matters most for ASS: the [Script Info] and [V4+ Styles] sections, every event's layer, style, name, margins and effect, karaoke timing, typesetting and Comment: lines all survive untouched. Formatting inside the text — <i>, <b>, {\pos(…)} — survives too.
Questions about the free tools
Are these tools really free?
Which subtitle formats are supported?
Do you keep the files I upload?
Can I process a whole season at once?
Is there an API for these?
/api/v1/tools (see the API reference), and every format converter has its own endpoint at /api/v1/convert (see the converter API reference). Both are open for now; if you're building against them, keep an eye out for API-key access when we launch it officially.