Translate an SRT or VTT file into Japanese on your own device, with every cue keeping its original start and end time. A note on length: Japanese subtitles are measured in characters, not words, and the limits are tight. Style guides commonly allow about 13 full-width characters per line, which is why professional Japanese subtitles condense dialogue heavily. Machine translation renders the whole line instead, so an accurate translation can still be too long to read in the time its cue is on screen. The tool does not trim, re-wrap or re-time anything, so the long cues are a job for a human editor.
How it works
- Drop the .srt or .vtt in Chrome 138 or later. Japanese is preselected as the target.
- Translate & download. The file keeps its format: an .srt comes back as an .srt and a .vtt as a .vtt, with the same timings.
- Go through the longest cues and cut them to what can be read in time. Check politeness too: each line is translated separately, so desu/masu forms and plain speech can alternate within one scene.
Questions
- How many characters fit in a Japanese subtitle line?
- A widely used limit is 13 full-width characters per line, with at most two lines per cue. Kanji, kana and full-width punctuation each count as one. Nothing on this page counts them for you, so check the longest cues by eye after translating, and condense the wording rather than lengthening the cue, which would push into the next line of dialogue.
- Can I burn Japanese subtitles into a video?
- Yes: switch to Burn in and drop the video with the translated file. One thing to know first: the burn-in renderer wraps long lines at spaces, and Japanese has none, so a long cue stays on a single line and can run past the edge of the frame. Put the line breaks into the cue text yourself, then check the preview, which draws a real frame with the real renderer.
- Does my file get uploaded?
- No. The models and all processing run inside your browser on your own device. You can verify this yourself: open your browser’s DevTools, watch the Network tab, and process a file: there are no uploads. After the first visit most tools also work fully offline.
- What is a two-point resync?
- A fixed shift fixes subtitles that are uniformly early or late, but not ones that drift further out over the runtime (a frame-rate mismatch). Pin the first and last line to their correct moments and every cue between them is stretched linearly. That is the standard fix, done locally.
- How does on-device translation work?
- Recent Chromium browsers ship a built-in translator that downloads language packs and runs locally. Where your browser offers it, this tool uses it, subtitle text included, and nothing is sent to a service. Where it does not, the page says so instead of quietly uploading.
- Burned-in vs a subtitle file: which do I want?
- A separate .srt/.vtt can be toggled and edited, and players render it crisply, so prefer it where you control playback. Burn-in re-encodes the video with the text drawn into the frames: it plays everywhere and cannot be turned off.