Practical register control
Tone Converter is tuned for Japanese workplace communication. It uses the selected register plus surrounding text and app context when available to avoid generic, prompt-shaped output.
Tone Converter
Match your Japanese to the relationship—not just the grammar rule.
Turn a completed Japanese passage into Casual, Polite, or Formal Business language, with a preview that keeps your original untouched until you approve it.
Kaku Rewrite
Original
資料見た。問題ないです。
Formal Business420 ms
資料を拝見いたしました。問題ございません。
Apply RewriteCancel
When the relationship changes the wording
Use it when a message is grammatically correct but too casual, too stiff, or mismatched for a teammate, manager, or client.
Choose the relationship in three steps
No keigo prompt engineering and no automatic replacement.
Select Japanese text
Choose one sentence or a cohesive passage in the active text field.
Pick the register
Choose Casual, Polite, or Formal Business from the Rewrite panel.
Review and apply
Read the rewritten Japanese, then apply it or keep your original.
Before and after
From quick draft to business-ready
The meaning stays the same while word choice and register adjust for a senior workplace relationship.
Before
資料見た。問題ないです。
After
資料を拝見いたしました。問題ございません。
Context only when requested
Tone Converter calls Kaku AI only after you select a register. It sends the selected passage and limited available context needed to produce the rewrite.
Change tone where the message lives
Open the Rewrite panel from supported chat, mail, document, and note fields without copying the passage into a separate AI chat.
Keep exploring Kaku
Install Kaku on your desktop.
Kaku is a lightweight desktop app — not a browser extension. Sign in with Google after install to enable cloud features.
macOSBeta.dmg · Apple Silicon & IntelmacOS 13+
Windows.exe · Windows 10 / 11 · x64Coming soon