English to Japanese

How good is it, measured

COMET 89.9 for English → Japanese, over 200 sentences of the FLORES-200 test set, with the checks running — the recipe that ships. At that score it reads naturally; you would edit wording, not meaning.

COMET is a standard automatic measure of translation quality, not a percentage of words correct; it is the number machine-translation research reports, which is why we report it rather than a figure of our own devising. We publish it for the 45 pairs we have actually run. A pair we have not measured gets no page and no number, because an interpolated score would be a guess presented as a fact.

Five real translations, unedited

These sentences come from FLORES-200, the public test set that translation research is measured on. They were chosen before anything was translated — the same five on every pair page — and each is shown exactly as Traxlate returned it on an RTX 3070, next to the translation a professional translator wrote for the same sentence.

A different word from the reference is not an error: two good translators rarely match word for word. What to look for is whether the meaning, the numbers and the names came through.

1. English — original

   "We now have 4-month-old mice that are non-diabetic that used to be diabetic," he added.

   Traxlate, on the device · 0.50 s

   「今では糖尿病を患っていた4か月齢のマウスが糖尿病を患わない状態になりました」と述べた。

   Human reference translation

   「我々が飼っている生後4か月のマウスはかつて糖尿病でしたが現在は糖尿病ではない、」と彼は付け加えました。

2. English — original

   For instance, they didn't have corn, nor tomatoes, nor potatoes, nor cocoa, and no ancient Roman ever tasted a turkey.

   Traxlate, on the device · 0.71 s

   例えば、彼らにはトウモロコシもトマトもジャガイモもココアもなく、古代ローマ人はトラウトを食べたこともなかった。

   Human reference translation

   例えば、そこにはトウモロコシもトマトもジャガイモもココアもなく、七面鳥を味わった古代ローマ人はいなかったわけです。

3. English — original

   Mass car ownership also leads to a higher incidence of accidents on the roads, which leads to the invention of new techniques in healthcare for repairing damaged bodies.

   Traxlate, on the device · 0.66 s

   また、自動車の大量所有は道路事故の発生率を高め、傷害を受けた身体を修復するための新しい医療技術の発明につながる。

   Human reference translation

   自動車の保有者増加は、道路事故発生率の増加につながり、結果として、負傷した身体を治療するための新技術が医療分野で開発されることになります。

4. English — original

   Severe weather is the generic term for any dangerous weather phenomenon with the potential to cause damage, serious social disruption, or loss of human life.

   Traxlate, on the device · 0.73 s

   厳しい天候（きょうしいてんこう）とは、被害や深刻な社会的混乱、人命の喪失を引き起こす可能性のある危険な天候現象を指す総称である。

   Human reference translation

   悪天候とは、物理的被害、深刻な社会的混乱、人命に関わる被害につながりうる危険な気象現象の総称です。

5. English — original

   Majorcan cuisine, like that of similar zones in the Mediterranean, is based on bread, vegetables and meat (specially pork), and uses olive oil throughout.

   Traxlate, on the device · 0.61 s

   マヨルカの料理は地中海の同じ地域と同じように、パン、野菜、肉（特に豚肉）を基盤にし、オリーブオイルを用いる。

   Human reference translation

   マヨルカ島の料理は、地中海の他の地域と同様に、パン、野菜、肉（特に豚肉）を主な食材とし、オリーブオイルを多用します。

Sentences: FLORES-200 devtest, by Meta AI, licensed CC BY-SA 4.0. Translated 2026-09-24.

What you can translate

• Text — type, paste or dictate, and read it back in Japanese.
• Documents — Word, PowerPoint, Excel, EPUB and subtitles, with the formatting kept rather than flattened.
• PDFs — including scanned ones, read on the device.
• Pictures — photograph a sign or a menu in English and read it in Japanese.

Why it stays on your device

The engine and the language pack are downloaded once and run locally. There is no English-to-Japanese API call behind this page: the server rung was removed in August 2026, so a hard sentence cannot quietly be sent away to be handled. That matters most for the documents people actually translate — contracts, medical letters, filings. The privacy model says exactly what does and does not leave, and the security page covers the rest.

What is checked before you see it

Each sentence is drafted, then checked for the failures that change meaning rather than style: a dropped negation, a changed number or amount, a name that went missing, a date that shifted. Where a check is not satisfied the sentence is redrafted. English and Japanese are covered by the language-specific tables built for 18 languages. The status line names the step it is on, and anything it could not settle is shown to you rather than hidden.

The other direction, and each language on its own

• Japanese to English — measured separately; the score differs by direction.
• English on Traxlate — script, voices, picture reading and what else is supported.
• Japanese on Traxlate — the same, for the target.

Other pairs we have measured

• Arabic → English
• Chinese → English
• English → Amharic
• English → Arabic
• English → Armenian
• English → Bengali
• English → Burmese
• English → Chinese
• English → French
• English → Georgian
• English → German
• English → Greek