Japanese to English subtitles, made in your browser
Drop in a Japanese video. Whisper writes the Japanese subtitles from its speech in this tab, then they are translated into English with every timing kept. The video is not uploaded. In desktop Chrome the translation is free and runs on your device too.
No account to try; burning into a video takes a free sign-in. No watermark. MP4, MOV, WebM and MKV.
How to make Japanese to English subtitles
This is the same tool as the free subtitle generator on the home page, used for one language pair.
- Choose the video on opensubs.app.
- Pick a model that knows Japanese. Base (about 80 MB) or Small (about 250 MB). Tiny is English only. The model downloads once and is cached.
- Generate from the audio. The language is detected for you, every four seconds, so a video that switches between Japanese and English is written down in both. You can also set Japanese yourself.
- Translate. In the Translate tab choose Into: English, pick a translator (below) and press Translate cues. If Translate from is left on detect and the browser says it cannot translate, set it to Japanese.
- Check and export. Every line is a text box. Then burn the English subtitles into an MP4 (a free sign-in), or save .srt, .vtt, .ass or .txt.
Already have a Japanese .srt or .vtt? Open it instead of a video and go straight to the Translate tab; no speech model is needed.
What is free, and what is paid
Writing down the Japanese is free and local in every browser that can run the recogniser. For the English, there are three translators, and only one of them is ours to charge for.
On this device
Chrome's built-in translator, in desktop Chrome 138 or later. No key, no account, nothing uploaded. Chrome downloads its Japanese to English model the first time. It translates literally, one sentence at a time. Firefox and Safari do not have it.
Claude, DeepL or an OpenAI-compatible API
Works in any browser. You pay the provider, not us; DeepL has a free tier. The OpenAI-compatible option also takes Ollama or LM Studio on your own computer. Only the subtitle text is sent.
OpenSubs credits
Our own backend, which reads the whole clip for context. $5 for 1,000 credits, with the price shown before the job runs. It needs an OpenSubs account, and sends the subtitle text, never the video.
How well it hears Japanese
Base and Small write Japanese; Tiny is English only. How well they hear it depends on the audio: accents, noise and background music make it worse, and names and specialist words are where you will correct most.
If your browser cannot run a model well, the Your own API key route for transcription sends the audio to a bigger model instead. That sends the audio (never the video) to the service you choose, and you pay them.
Japanese and English on screen together
For language learners, or viewers who read some Japanese, keep both: the original and the English stack on the same subtitle, either one on top, and both burn into the video. Japanese fonts are bundled, so the characters render in the burned MP4. See bilingual subtitles, and translate subtitles for how translation keeps every timing.
- Timings are not editable: you can rewrite a line, not move it.
- Machine translation is a first draft. Read it before you publish.
- Looking for ready-made English subtitles for a film or an anime? That is a different search: see subtitle sites.
Questions
Can I make Japanese to English subtitles for free?
Yes. Transcribing the Japanese is free in the browser, and in desktop Chrome 138 or later the English translation is free too, on your own device. In other browsers you can use your own Claude, DeepL or OpenAI-compatible key, or pay in OpenSubs credits.
Is my video uploaded?
No. Whisper runs in your browser and the video is read from your disk. With the on-device translator nothing is sent at all; a cloud translator receives only the subtitle text.
Does it work in Firefox or Safari?
The transcription does. The free on-device translator is Chrome's, so in Firefox or Safari you translate with your own API key or with OpenSubs credits.
Can I translate a Japanese SRT file I already have?
Yes. Open the .srt or .vtt, choose English in the Translate tab and run it. No video and no speech model are needed.
Can I show the Japanese and the English together?
Yes. Turn on bilingual subtitles to stack both on each line, with either language on top, and burn them into the video or export them.