AnyTool
Your files never leave your device. All processing happens locally in your browser.

How do I translate an SRT or VTT subtitle file online?

Open AnyTool Subtitle Translator, upload or paste your .srt or .vtt file, pick the target language and click Translate. The tool translates only the cue text and never the timestamps, then lets you download SRT or VTT (or a bilingual original-plus-translation file). Translation runs on-device with the browser built-in AI (Chrome 138+); without it you can edit cues by hand or use the offline phrasebook. The conversion, retiming and CPS-check tools always work. Nothing is ever uploaded.

  • Parses SRT and WebVTT, keeping cue index, timestamps and multi-line text
  • Translates cue text only — timestamps are never altered
  • On-device AI translation (Chrome 138+) or offline phrasebook fallback
  • SRT ⇄ VTT convert, shift, scale, fps presets, fix overlaps, strip tags
  • Per-cue characters-per-second check; bilingual output — 100% in-browser

What is

Subtitle Translator

A subtitle translator parses a subtitle file (such as SRT or WebVTT), translates each cue’s spoken text into another language while preserving the original start and end timestamps, and re-assembles the file so it stays in sync with the video.

Text Tools

Related terms

SRT TranslatorVTT ConverterCaption TranslationCharacters Per Second

Frequently Asked Questions

No. Only the caption text is translated; the start and end timestamps stay exactly the same so the subtitles stay in sync.

AnyTool Subtitle Translator separates each cue’s timing from its text. It sends only the text to the on-device translator and writes the original timestamps straight back into the output, so a translated SRT or VTT lines up with the video exactly as the source did. You can still shift or scale timing yourself with the retiming tools if needed.

Nothing is uploaded. Parsing, translation, editing and re-assembly all run in your browser, and the page works offline once loaded.

The tool is 100% client-side. Your subtitle file is read, parsed, translated and rebuilt entirely in your browser with no server and no cloud translation API, so it is safe for unreleased films and confidential footage. On-device AI translation also keeps the text on your machine.

Conversion, retiming, overlap fixing and CPS checks still work, and a built-in offline phrasebook gives a word-by-word draft you can correct by hand.

Full sentence translation needs a browser with built-in on-device AI such as desktop Chrome 138 or later. Because a purely client-side tool can never reach a cloud service, on browsers without that AI the translator falls back to an offline phrasebook word-by-word pass for supported language pairs, or leaves the original text for you to edit. Every editing, conversion and retiming feature works in any browser.

It measures reading speed per cue. Around 17 CPS is comfortable; the tool flags cues above 17 (amber) and above 21 (red) as hard to read.

Characters per second divides a cue’s visible character count by its on-screen duration. Subtitling guidelines suggest keeping cues at or under about 17 CPS for comfortable reading, with broadcast caps often near 17 to 21. The tool shows each cue’s CPS and warns when it is too fast, so you can lengthen the timing or shorten the text.

Detailed Explanation

Methodology

How the Subtitle Translator Works

AnyTool Subtitle Translator parses an SRT or WebVTT file entirely in the browser. Each cue is decomposed into its index, start and end times (stored as milliseconds) and its multi-line text. Only the text is passed to the translator; the millisecond timings are written straight back into the output, so the translated file stays frame-accurate. Re-assembly serialises cues to SRT (comma decimal) or VTT (dot decimal with a WEBVTT header).

  • Supports SubRip (.srt) and WebVTT (.vtt), including multi-line cues
  • Timestamps are kept as milliseconds and never translated
  • Format is auto-detected from the WEBVTT header or timing separator
  • Output re-assembles to SRT or VTT, or a bilingual stacked file
  • All parsing, editing and serialising is client-side JavaScript
How It Works

On-device Translation and Honest Fallbacks

When the browser exposes the experimental on-device Translator API (desktop Chrome 138+), each cue is translated locally and the first use of a language pair downloads a browser-managed language pack with a progress bar. Because the tool is 100% client-side it never calls a cloud translation service, so on browsers without that AI it falls back to a bundled offline phrasebook for supported pairs, or leaves the original text for manual editing. The subtitle editing, conversion and retiming features work in every browser regardless.

  • On-device AI translation keeps cue text on the user’s machine
  • Language packs download on first use, then work offline
  • Offline phrasebook gives a word-by-word draft for supported pairs
  • No cloud translation API and no upload, ever
  • Cues remain fully editable by hand at any time
How It Works

Reliable Subtitle Utilities and CPS Checks

Beyond translation, the tool offers fully reliable subtitle utilities: SRT to VTT conversion (and back), millisecond timing shift, linear scale, frame-rate conversion presets (23.976, 24, 25, 29.97, 30 fps), overlap fixing with renumbering, and formatting-tag stripping. A per-cue characters-per-second (CPS) check measures reading speed, flagging cues above roughly 17 CPS as hard to read so editors can lengthen timing or trim text.

  • SRT ⇄ VTT conversion preserves timing and text exactly
  • Shift, scale and fps presets retime every cue at once
  • Fix-overlaps sorts cues and nudges overlapping ones apart
  • CPS check bands cues as ok (≤17), warn (≤21) or high (>21)
  • Bilingual output stacks the original above the translation
Subtitle translation: in-browser (AnyTool) vs typical online subtitle translators
CapabilityAnyToolTypical online translators
File handlingParsed in your browserUploaded to a server
PrivacySubtitles never leave deviceFiles stored or queued in the cloud
TimestampsAlways preserved exactlyUsually preserved
Editing & conversionSRT⇄VTT, shift, scale, fps, CPSOften translate-only
Offline useYes — utilities work offlineNo
Translation engineOn-device AI or phrasebookCloud machine translation
Cost / signupFree, no signupOften metered or gated

Cloud subtitle translators can retain uploaded files; AnyTool parses, translates and re-assembles locally and uploads nothing. Full machine translation depends on the browser’s on-device AI, while conversion and retiming always work.