Which AI writing tool fits you?

ChatGPT, Claude and Gemini in a tab. Grammarly. Copilot in Windows and Office. And Rithere. Who each one is for, in plain words.

5 min read Checked against official sources, October 2026

Written by Rithere's developer. A guide that sent everyone to Rithere would be useless, so this one doesn't. The small numbers link to each official source, checked October 2026.

Three kinds of AI writing help

The easiest way to sort them: where do they act on your text?

Checks as you type

Underlines mistakes without being asked.

Grammarly

Works where your text is

Select text, ask, and the result appears right there.

Rithere, Copilot, Grammarly's sidebar

Works in its own window

Very capable, but you carry text in and out.

ChatGPT, Claude, Gemini

Who should use what

You live in Word and Outlook

  • Copilot. Built in, works on the whole document, and comes with Microsoft 365 Personal and up.1,2
  • Rithere adds: Slack, Gmail, Notion and the rest.

You mainly want fewer typos

  • Grammarly. Live suggestions on Windows, Mac, browsers and phones.3
  • Rithere adds: bigger rewrites with your own instructions.

You research and think out loud

  • ChatGPT, Claude or Gemini. Files, long chats, web search. All three have free plans.4,5,6
  • Rithere adds: the small edits not worth a trip to another window.

You write all day, in many apps

  • Rithere. Highlight, press a key, done, with prompts you wrote once.7
  • Not for: live grammar checks, files or images, Mac.

Your text must stay on your PC

  • On-device tools: Click to Do's rewrites on a Copilot+ PC (a newer PC with a built-in AI chip),8 or PowerToys Advanced Paste with an AI app that runs on your PC, which takes some setup.9
  • Rithere sends text to Google Gemini, so it isn't a fit.

Your company picks the tools

  • Whatever IT has approved. Copilot, Grammarly, ChatGPT and Claude, among others, sell business plans.10,3,11,5
  • Rithere has no business plan yet. Ask before installing it at work.

Tick what describes you

The count only adds up your own ticks. More than one tool can cover a line.

Tick the lines that describe what you need.

Will Microsoft make a separate app unnecessary?

Fair question. Microsoft is building AI into Windows and Office: Copilot in Word and Outlook,1,12 Click to Do on Copilot+ PCs,8 and, previewed in November 2025, writing help for "any text box in any app".13 Google's Gemini app on the Mac already rewrites highlighted text in any app by voice, with a setting turned on.14 Gemini's Windows app doesn't do that yet, and Google says more is coming.15

So for some people the built-in tools will be enough. If you're in Office all day, on a Copilot+ PC, with Microsoft 365 paid for, you may never need Rithere. What still sets it apart today:

  • Your prompts, your shortcuts. Each saved instruction on its own key.7
  • The PC you already own. Any 64-bit Windows 10 or 11 PC.16
  • Almost every app, not just Office.
  • Answers without edits, beside your cursor.17
  • No subscription. Free today.16

We'll update this page as the built-in features ship, including if they close the gap.

Privacy: clear answers

Read any AI tool's privacy policy and ask plain questions. Here's what each company says.

Tool Trains on your text? What's kept
Rithere NoUses Google's Gemini AI on a paid plan, which Google doesn't use to improve its products.18,19 Rithere's servers don't store your text. Google keeps it 55 days to check for misuse, and its staff may review flagged requests. Your History stays on your PC.18,20
ChatGPT By defaultOn personal plans; you can opt out.21 Chats stay until you delete them, then are erased within 30 days.22 For temporary chats, a copy is kept up to 30 days.23
Claude Your choiceOn Free, Pro and Max.24 Chats stay until you delete them, then are erased within 30 days; copies can be kept up to 5 years if you allow training.25
Gemini By defaultIts activity setting is on by default for adults; some chats are read by people.26,27 Auto-deletes after 18 months by default; 72 hours with that setting off.27
Grammarly By defaultFor individuals; you can opt out.28 Saved documents stay until you delete them.29
Copilot NoNot for Microsoft's core AI models, in the current app (from August 2026) or Microsoft 365 home apps.30,31 You can delete your history;30 work accounts get Microsoft's work-data safeguards.32

What they cost

Tool Free plan First paid plan (US)
RithereEvery featureNone yet
ChatGPTYesLimited tools.4Go $8, Plus $20 a month11
ClaudeYesLimit resets every 5 hours.5Pro $20 a month, or $17 a month paid yearly5
GeminiYes6AI Plus $4.99, AI Pro $19.99 a month6
GrammarlyYes100 AI prompts a month.3Pro $12 a month paid yearly, or $30 month to month3
CopilotYesA limited free app.10Microsoft 365 Personal $9.99 a month10

Where Rithere fits, honestly

Rithere is small on purpose. It doesn't read files, make images or remember you between chats. It does one thing the big assistants make awkward: change the text you highlighted, in the app you're in, with an instruction you saved, in one keystroke. It's free today and works alongside everything above.16

For the technically curious
  • Rithere's proxy holds text only while Gemini writes the answer; its logs record that a request happened, not what it said.18 Full policy: privacy.
  • Google's Gemini API terms treat paid and free use differently; the paid terms are the ones that apply to Rithere.19,18
  • Claude's incognito chats aren't used for training.33 ChatGPT feedback (thumbs up or down) can still be used after opting out.21

FAQ

It depends on the job. For typos as you type: Grammarly Free. For research and long chats: ChatGPT, Claude or Gemini. For rewriting highlighted text in any Windows app: Rithere, which is free in full today.

Maybe not, if you work mostly in Word and Outlook with Microsoft 365. Rithere helps most when you write across many apps, on any 64-bit Windows PC, with your own prompts.

No. Its servers don't store your text, and it uses Google's Gemini AI on a paid plan, which Google doesn't use to improve its products. Google keeps your text 55 days only to check for abuse.18

Sources

Official pages, accessed 16 October 2026.

  1. Edit content and rewrite with Copilot in Word
  2. Copilot in Microsoft 365 subscriptions, FAQ
  3. Grammarly plans
  4. ChatGPT free tier FAQ
  5. Claude pricing
  6. Gemini subscriptions
  7. Rithere Prompts
  8. Click to Do, Microsoft Support
  9. Advanced Paste, Microsoft Learn
  10. Copilot pricing for individuals
  11. ChatGPT plans and pricing
  12. Draft an email with Copilot in Outlook
  13. Ignite 2025: Windows at the frontier of work
  14. Gemini release notes
  15. Gemini desktop app
  16. Rithere FAQ
  17. Rithere Ask
  18. Where your text goes (Rithere)
  19. Gemini API terms
  20. Gemini API usage policies (abuse monitoring)
  21. OpenAI: how your data is used to improve model performance
  22. Chat and file retention in ChatGPT
  23. Temporary chat in ChatGPT
  24. Anthropic: updates to consumer terms
  25. Claude: how long data is kept
  26. Gemini Apps Activity
  27. Gemini Apps Privacy Hub
  28. Grammarly: product improvement and training
  29. Grammarly privacy
  30. Copilot app activity history
  31. Copilot in Microsoft 365 apps for home: your data
  32. Copilot privacy and protections (work accounts)
  33. Claude incognito chats

The one-to-one comparisons

VS

Rithere vs Microsoft Copilot

Do you still need a separate app if you live in Office?

Read it
VS

Rithere vs Grammarly

Grammar as you type, against AI on a hotkey.

Read it
VS

Rithere vs ChatGPT

The copy-and-paste round trip, and when it's worth it.

Read it

Write all day on Windows? Try the shortcut.

Highlight text in any app, press a key, done. Free today, no API key, and it works alongside the rest.

Download Rithere All comparisons