While handling a Kindle publishing (KDP) application, have you ever gotten stuck on something like this?
“Does the furigana for the book title have to be full-width katakana?” “Romaji inputwhat is that? Hepburn? Passport notation? How should I write it?” “I don’t know how to enter the reading for a title that includes English or numbers…”
You finally finish writing the manuscript, only to get stuck at the very end on the publication application (entering the book details), which is incredibly stressful. In particular, KDP requires **furigana and romaji input for the ‘title’ and ‘author name,’** and the format is strict.
So this time, we developed and released a **“Kindle Publishing Application Romaji Conversion Tool”** that finishes this annoying task in just **one second**.
It converts not only kanji, but also titles that include English and numbers, perfectly according to KDP specifications. It’s completely free, so please bookmark it and make use of it!
Romaji & Furigana Conversion Tool for Kindle Publishing Applications
How to use it is simple. Just enter the title or author name and press the “Run Conversion” button. Copy the generated text and paste it into the KDP dashboard.
Kindle出版用 変換マスターツール
漢字・かな・英数 → KDP仕様のカタカナ & ローマ字(読みやすい/最安全)+英語案
ご利用上の注意点
-
英単語(アルファベット)の扱い:
「Kindle」「AI」「WordPress」などの主要IT用語は自動でカタカナ化されますが、一般的な英単語や固有名詞(例:Blueberry等)は意図通りにならない場合があります。
その場合は、最初からカタカナ表記に直して入力すると安定します。 -
ローマ字は2種類出力されます:
用途に合わせて 読みやすい(スペースあり) と KDP最安全(小文字・スペースなし) を出します。
KDPの入力で迷ったときは、基本的に 「最安全」 を優先してください。 -
固有名詞の読みは必ず確認:
人名・地名・ペンネームなどは読みが揺れることがあります(例:角田→カクタ/ツノダ)。
結果が違う場合は、フリガナを修正して 「再変換」 を押し、正しいローマ字に寄せてください。 -
AI整形(OpenAI)について:
「AI整形」 を押すと、入力内容と現在の変換結果(ヒント)をもとに、KDP向けに フリガナ(全角カタカナ)/ローマ字(読みやすい)/ローマ字(最安全)/英語 をまとめて整形し、 結果欄に上書きします(通信が発生します)。
※最終的な表記は必ず目視で確認し、必要なら手で修正してください。 -
AI英語生成(AI生成)について:
「AI生成」 は、入力した タイトル/サブタイトル/著者名 をもとに、KDP向けの英語案だけを作成します(通信が発生します)。
誇大表現、ランキング・無料・プロモーション表現、キーワード詰め込み等は避け、必ず内容確認・調整してください。 -
利用制限(ログイン・回数制限):
コスト事故防止のため、設定により ログイン中のみ 利用できる場合があります。
また、アクセス集中や誤操作防止のため 1時間あたりの利用回数に上限があります(上限に達すると一定時間利用できません)。
無料新規ユーザー登録はこちら -
送信される情報について:
AI機能を使うと、フォーム入力(タイトル/サブタイトル/著者名)と、参考情報として変換結果(ローマ字など)が、 サーバー経由で外部APIへ送信されます。個人情報や機密情報の入力は避けてください。 -
通信エラー・生成失敗について:
APIキー未設定、通信状況、外部サービス側の混雑などにより、AI生成に失敗する場合があります。
その場合は時間を置いて再実行するか、各欄を手動で入力してください。 -
AI生成結果の上書きについて:
「AI生成」 の英語は、フリガナの 「再変換」 をしても基本的に消えない設計です(意図せず消えないようにしています)。
ただし 「AI整形」 は、フリガナ/ローマ字/英語をまとめて上書きします。必要なら先にコピーして退避してください。
Change history (update log)
December 21, 2025 v4.5.1 (AI formatting button added)
We added a one-click feature for logged-in users that formats and overwrites KDP metadata (katakana furigana / two types of romaji / English) all at once.
- “AI formatting” button added(Processes title / subtitle / author name together)
Based on the Japanese text you entered and the existing conversion results (hints), it batch-formats the notation for KDP. - Expanded formatting targets(Format everything for KDP)
- Katakana furigana (full-width katakana)
- Romaji (easy to read, with spaces)
- Romaji (KDP safest, lowercase with no spaces)
- English (title / subtitle / author name)
- Added explanatory text on screen (to prevent misunderstandings)
A small note now appears below the AI formatting button so users understand that it uses communication and may overwrite data. - Restricted to logged-in users only (to prevent cost accidents)
If you are not logged in, you cannot use it and a guidance message will be shown. - Added usage limits (to prevent repeated clicks and traffic spikes)
We set a limit on the number of uses per hour; once the limit is reached, it cannot be used for a certain period.
✅ With this update, in addition to the existing automatic conversion + manual correction,you can also use AI to organize everything into a “submission-ready final form”(a feature for logged-in users).
December 18, 2025 v4.5.0 (AI English generation button added)
We made it possible to assist with creating KDP English metadata (title / subtitle / author name)with a single clickfor logged-in users.
- “AI Generate” button added (generate title / subtitle / author name together)
Based on the Japanese text you enter, it automatically generates natural English options suitable for KDP.
*The English suggestions are for reference; we recommend reviewing and adjusting them before final use. - Added restriction to logged-in users only (to prevent cost accidents)
AI generation, depending on settings, is available only to logged-in users.
If you are not logged in, a message saying “Available only for logged-in users” will be shown. - Added usage limits (to prevent traffic spikes and accidental operation)
To prevent cost increases caused by repeated clicks or traffic spikes, we set a limit on the number of uses per hour.
Once the limit is reached, the feature cannot be used for a certain period. - Preservation of AI-generated results (designed not to disappear unexpectedly)
We changed it so that English generated by AI is basically not overwritten even if you perform furigana “reconversion.”
If you want to change the input and generate again, after editing, press “AI Generate” once more. - Clarification of transmitted information (for transparency)
When AI generation runs, the form inputs (title / subtitle / author name) and, as reference information, romaji (easy-to-read version) are sent to an external API.
Please avoid entering personal or confidential information.
✅ With this update, in addition to romaji and furigana conversion,it became possible to quickly assist only the people who need it with creating English metadata(a feature for logged-in users).
December 13, 2025 v4.3.0 (Added furigana editing → reconversion feature)
We improved the tool so that when users feel the “conversion result is wrong,” they can correct it themselves and finish it accurately.
- Made furigana (for KDP, full-width katakana) editable
You can now edit the automatically converted furigana on the spot whenever necessary. - Added a “Reconvert” button (title / subtitle / author name)
After correcting the furigana, pressing “Reconvert” will regenerate romaji (for KDP submission) from the corrected furigana.
Even if the automatic conversion misses proper nouns or reading variations (for example: Kakuta/Tsunoda for Kadota), you can adjust it to the correct romaji. - Automatic handling of hiragana input (to prevent mistakes)
Even if hiragana is mixed into the furigana field, it now gets normalized internally into katakana.
This makes it less likely to break even if you make a small input mistake. - Added guidance text (clear path forward)
If the conversion result is wrong, the screen now instructs users to correct the furigana and reconvert.
✅ With this update, instead of simply leaving everything to automatic conversion, the design now lets **users reliably steer the final result toward the correct answer**.
This helps reduce the risk of mismatches and application errors when submitting to KDP.
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