Free
Everything you need to try Kaku and use it occasionally.
$0forever
Download for free- Unlimited on-device grammar correction
- 5 AI rewrite credits per day (resets daily)
- All three keigo registers
- On-device privacy
Simple pricing. Honest defaults.
Free covers casual use forever — 5 rewrites a day, every day. Pro adds a 2,000-credit monthly pool the day five a day starts to feel small.
Pro
5 free credits/day + a 2,000-credit monthly overflow pool for daily writers.
$9/ month
Upgrade to Pro- Unlimited corrections
- 5 free credits/day + 2,000 monthly overflow
- Weekly progress digest
- Error-pattern tracking
- Priority support
Billed in USD. Switch to a JP-locale browser to see JPY pricing (¥1,480 / month).
Everything in Free, plus more in Pro.
What you get on each plan.
| Feature | Free | Pro |
|---|---|---|
| Inline correctionGrammar, particle, vocabulary, keigo — at the cursor. | Daily limit | Unlimited |
| Tone conversionRewrite selected text into the register you need. | 5 / day | 5 / day + 2,000 / month |
| All three keigo registers普通体 · 丁寧語 · ビジネス丁寧語. | Included | Included |
| Plain-English explanationsEvery non-trivial correction explained. | Included | Included |
| Works in every desktop appChat, mail, docs, notes — not a browser extension. | Included | Included |
| On-device correctionSource text never leaves your machine. | Included | Included |
| Weekly progress digestSee your top mistakes and improvement trends. | Included | |
| Error-pattern trackingPer-rule apply rates surfaced over time. | Included | |
| Priority supportFaster turnaround on questions and reports. | Included |
What Pro unlocks.
The three things Pro subscribers tell us made it worth the upgrade.
Daily basics on the house. Heavy days on Pro.
Everyone gets 5 free credits a day. Pro adds a 2,000-credit monthly pool that kicks in only when you blow past your daily five — so casual days cost nothing extra and heavy days don't fall off a cliff.
See yourself improve.
Weekly digest emails surface your most common mistakes and your apply rate per category. Track progress at the level of grammar rules, not vibes.
Direct line when you need it.
Bug reports, feature questions, and account issues get a same-business-day response, not a queue.
Billing, plainly.
Short answers to the questions before-the-card-charges.
Can I switch between monthly and annual?
Yes. Switch from Settings → Subscription. Annual takes effect on your next renewal; switching from annual to monthly applies after your current annual period ends.
What happens when I cancel?
Cancellation stops future renewals. Your current period continues until its end date, then your account reverts to the Free plan (5 AI rewrite credits per day). Your account, history, and settings remain intact.
Do you offer refunds?
Except where required by law, all payments are non-refundable. We may grant a pro-rata refund in exceptional circumstances. Statutory consumer-protection rights (e.g., the EU right of withdrawal) are not affected.
Are taxes included?
Prices shown are exclusive of taxes, levies, or duties imposed by your jurisdiction unless explicitly stated. Stripe calculates and adds applicable taxes at checkout.
Do you have team or education plans?
Team plans are on the roadmap. For classroom and team rollouts of 10+ seats, email hello@kaku.example — we'll work with you directly until self-serve team plans ship.
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.
Installers are not yet available. Want to be notified when builds ship? Drop us a line.