Windy TranslateJapanese translation and speech-to-text models ja
2 models into Japanese, 21 from Japanese, 14 speech-to-text. Best scored into Japanese: Chinese to Japanese (chrF++ 1.4). Best scored from Japanese: Japanese to English (chrF++ 44.7).
Which open models work for Japanese?
Windy Translate lists 2 open translation models into Japanese and 21 from Japanese. All of them can be downloaded from Hugging Face and run on your own hardware. By licence: 20 Apache-2.0 and 3 CC-BY-4.0 (terms and attribution text: licensing). 19 of them have a screening score on FLORES-200. The best scored into Japanese is translate-tc-big-zh-ja (chrF++ 1.4, Not recommended). The best scored from Japanese is translate-ja-en (chrF++ 44.7, Usable).
With English. English to Japanese: translate-windy-hplt-en-ja (not yet scored). Japanese to English: translate-ja-en (chrF++ 44.7, Usable), the best of 2 direct models. To translate between Japanese and a language with no direct model, you can go through English with these two.
By band, the scored Japanese models are 9 Usable, 8 Limited and 2 Not recommended (Excellent is chrF++ 60 or more, Good 45 to 60, Usable 30 to 45, Limited 15 to 30). A score is a 48-sentence screening of news and encyclopedia text, not a measure of accuracy, and a difference of a point or two is noise. How we measured.
Speech-to-text. 2 speech-to-text models made for Japanese: listen-windy-lingua-ja and listen-windy-lingua-ja-ct2. Also, Whisper's tokenizer lists Japanese as one of its languages, so all 12 multilingual Whisper-based models here can transcribe it: see the speech models. Accuracy differs a lot between languages and model sizes, and this site has not measured speech accuracy.
Each model page has a short snippet to download and run the model yourself, its licence and attribution text, and its score where there is one. Pick the best scored model for your direction, then try it on a few sentences of your own text: a screening score is a starting point, not a guarantee.
Into Japanese
| Model | chrF++ (FLORES-200 dev) | Licence |
|---|---|---|
| Chinese to Japanese best scored translate-tc-big-zh-ja | 1.4 Not recommended | CC-BY-4.0 |
| English to Japanese translate-windy-hplt-en-ja | score withheld | CC-BY-4.0 |
From Japanese
| Model | chrF++ (FLORES-200 dev) | Licence |
|---|---|---|
| Japanese to English best scored translate-ja-en | 44.7 Usable | Apache-2.0 |
| Japanese to Portuguese translate-ja-pt | 39.8 Usable | Apache-2.0 |
| Japanese to Italian translate-ja-it | 37.9 Usable | Apache-2.0 |
| Japanese to Dutch translate-ja-nl | 36.4 Usable | Apache-2.0 |
| Japanese to Spanish translate-ja-es | 35.2 Usable | Apache-2.0 |
| Japanese to French translate-ja-fr | 34.9 Usable | Apache-2.0 |
| Japanese to German translate-ja-de | 34.8 Usable | Apache-2.0 |
| Japanese to Bulgarian translate-ja-bg | 33.0 Usable | Apache-2.0 |
| Japanese to Russian translate-ja-ru | 31.4 Usable | Apache-2.0 |
| Japanese to Turkish translate-ja-tr | 30.0 Limited | Apache-2.0 |
| Japanese to Swedish translate-ja-sv | 30.0 Limited | Apache-2.0 |
| Japanese to Polish translate-ja-pl | 29.1 Limited | Apache-2.0 |
| Japanese to Finnish translate-ja-fi | 28.9 Limited | Apache-2.0 |
| Japanese to Vietnamese translate-ja-vi | 28.2 Limited | Apache-2.0 |
| Japanese to Danish translate-ja-da | 25.8 Limited | Apache-2.0 |
| Japanese to Hungarian translate-ja-hu | 25.7 Limited | Apache-2.0 |
| Japanese to Hebrew translate-ja-he | 15.2 Limited | Apache-2.0 |
| Japanese to Serbo-Croatian translate-ja-sh | 2.4 Not recommended | Apache-2.0 |
| Japanese to Arabic translate-ja-ar | not in FLORES-200 | Apache-2.0 |
| Japanese to Malay translate-ja-ms | not in FLORES-200 | Apache-2.0 |
| Japanese to English translate-windy-hplt-ja-en | not yet scored | CC-BY-4.0 |
Japanese speech-to-text
| Model | Formats | Licence |
|---|---|---|
| listen-windy-lingua-ja | safetensors | Apache-2.0 |
| listen-windy-lingua-ja-ct2 | ct2-int8 | Apache-2.0 |
Scores: chrF++ on FLORES-200 dev, 48 sentences, measured 2026-08-04. Method.