“Free AI writing tool” can mean very different things. One product is a general chatbot that happens to write well. Another is a grammar checker with a limited bundle of AI prompts. A third is a paraphraser that caps how many words you can paste in. Comparing them on the same sample paragraph hides these differences and rewards whichever tool suits that paragraph.
This guide offers a fair comparison method, then applies it to five free tiers: ChatGPT, Claude, Microsoft Copilot, Grammarly and QuillBot. We concentrate on what the vendors document about limits, features and data, and we leave out any claim about whose prose is better.
How we researched this: we did not run hands-on tests for this article. It is based on the vendor’s own documentation and public sources, checked on 11 November 2026. Features and prices change, so confirm details on the vendor’s site before you buy.
Key takeaways
- These five tools fall into two groups: general assistants (ChatGPT, Claude, Copilot) and focused writing utilities (Grammarly, QuillBot). Compare within a group first.
- Grammarly’s pricing page lists 100 AI prompts per month on Free, and QuillBot’s help centre lists 20 AI Chat queries per day and a 125-word paraphraser limit on its free plan.
- ChatGPT’s free tier FAQ promises “unlimited everyday text chats” subject to safeguards, while Claude’s pricing page describes limited usage in 5-hour and weekly windows.
- Check the data terms: OpenAI says consumer content may be used for training by default unless you opt out, and we could not confirm equivalent wording for the others.
- A fair test uses the same drafts, a fixed rubric and a record of when each tool hit its limit.
Why compare these
Most people who write for work try more than one free tool, and then drift towards whichever one they opened first. A structured comparison costs an hour and can save months of using the wrong tool. It also protects you from a common trap: a free tier that works well for a quick test but hits a limit the moment you use it daily.
Two kinds of tool
General assistants take open instructions: draft this email, shorten this section, explain this term. Focused utilities do narrower jobs, such as correcting grammar, adjusting tone or paraphrasing a passage. They are not direct substitutes, and many writers use one of each. If you want to understand the model behind the assistants, our explainer on what a large language model is is a good start.
Quick overview table
| Tool | Type | Free tier, as documented |
|---|---|---|
| ChatGPT | General assistant | Unlimited everyday text chats, subject to abuse safeguards; separate limits on uploads, images, voice and other tools |
| Claude | General assistant | Limited usage in 5-hour and weekly windows; access limited to Sonnet and Haiku models |
| Microsoft Copilot | General assistant | Free for general questions; sign-in optional; sign-in adds chat history, longer conversations and more |
| Grammarly | Writing utility | Writing without mistakes, tone detection and 100 AI prompts per month |
| QuillBot | Writing utility | Paraphraser up to 125 words, two modes, 20 AI Chat queries per day |
Criteria that matter
- Limits you will hit. Words per input, prompts per month, chats per day, usage windows.
- Features behind the paywall. Tone adjustment, plagiarism checks, longer inputs.
- Fit with your workflow. Browser, desktop apps, document editors.
- Data handling. Training use, retention, opt-outs.
- Quality for your kind of writing. Needs your own test.
- Cost to move up. What the first paid tier costs and gives.
Free limits
Assistants: limits described in words
OpenAI’s free tier FAQ describes “unlimited everyday text chats”, subject to abuse-prevention safeguards, with separate limits for file uploads, image creation, voice, data analysis and other tools. The page does not give numbers for those. It also notes that ads may appear in certain countries.
Claude’s pricing page says the Free plan has limited usage in both 5-hour and weekly windows, and that access is limited to Sonnet and Haiku models. It lists web search, file creation, code execution, memory, app connectors and Artifacts as included. It adds that how fast you reach a limit depends on the model, the length of your chats and the size of your files.
Microsoft’s support page, dated 9 November 2026, says Copilot is available at no cost for general questions and that sign-in is not required. Signing in with a personal account adds chat history, image creation, longer conversations and voice interactions. The page notes that usage limits apply to Copilot features inside paid Microsoft 365 plans.
Utilities: limits described in numbers
Grammarly’s plans page lists the Free plan as including writing without mistakes, tone detection and 100 AI prompts per month. It lists tone adjustment, full-sentence rewrites, plagiarism detection and AI text detection as unavailable on Free.
QuillBot’s help centre gives the clearest numbers. The table below reproduces them for the free plan against Premium.
| QuillBot feature | Free | Premium |
|---|---|---|
| Paraphraser length | Up to 125 words | Unlimited |
| Paraphraser modes | 2 (Standard and Fluency) | 9 |
| Summarizer | Up to 1,200 words | Up to 6,000 words |
| AI Chat | 20 queries per day | Unlimited |
| Plagiarism checker | Not included | 25,000 words per month |
| AI Detector | Up to 1,200 words, 10 scans per day | Unlimited |
Numbers help you plan. A 125-word paraphraser limit is easy to work around for a short paragraph and painful for an essay. A 100-prompt monthly allowance is plenty for occasional polish and tight for daily drafting.
Writing features by tool
ChatGPT
The free tier lists web search, data analysis, image and file uploads, image creation and a 500 MB library. You can use GPTs built by others, but creating or publishing them is not available on personal accounts.
Claude
Beyond chat, the Free plan includes file creation, code execution, memory and Artifacts, which are standalone documents or pages shown beside the chat. Claude Code, Projects and Opus are listed on Pro, not Free.
Microsoft Copilot
Microsoft describes core free features as AI chat for writing and summarising, real-time web-based answers and summaries of webpages in Edge. Deeper integration with Word, Outlook and other desktop apps is described as a feature of paid Microsoft 365 plans, and only the subscription owner gets Copilot in the desktop apps.
Grammarly and QuillBot
Grammarly leans towards correction and tone. QuillBot leans towards rewriting, with modes, a summarizer, translation and extras such as image generation (3 per day on free) according to its help centre. Both are narrower than an assistant, which is a strength if your job is polishing rather than drafting.
Privacy and data
| Tool | What we could confirm |
|---|---|
| ChatGPT | OpenAI says content from consumer services may be used to train models by default, with business offerings excluded. You can opt out through its privacy portal or data controls. |
| Claude | Anthropic’s pricing page says Team plans include no model training on your content by default. We did not confirm the equivalent wording for the Free plan. |
| Copilot, Grammarly, QuillBot | We did not read a training statement for the free tiers, so we make no claim. |
The practical rule is simple: do not paste confidential drafts, client names or unpublished figures into any free tool until you have read its current data terms. Our guide on protecting company data when using AI tools sets out a short policy you can adopt.
Pricing models
Checked on 11 November 2026. Confirm on each vendor page.
| Tool | First paid tier, as listed |
|---|---|
| Grammarly | Pro at $12 USD per month on the page we read, with a free trial; 2,000 AI prompts per member per month |
| QuillBot | Premium at $8.33 USD per month billed annually; the page also showed a $5.00 figure that may be promotional, so check at checkout |
| Claude | Pro at $17 per month billed annually or $20 per month billed monthly |
| ChatGPT | Plans named Go, Plus, Pro, Business and Enterprise; the captured pricing page did not show dollar amounts for us |
| Copilot | Free; Microsoft 365 plans (Personal, Family, Premium, Pro) include Copilot Chat with usage limits; prices not confirmed here |
For a method to read these pages without being caught by billing terms, see how to read an AI tool’s pricing page.
Who each suits
- ChatGPT: best for people who want a general drafting partner with web search, if they review data settings and accept unpublished tool limits.
- Claude: best for people who work with long files and documents, if the limited usage windows still cover a working day.
- Copilot: best for people who want no-cost access without an account, or who plan to move into Microsoft 365, if they accept fewer free features.
- Grammarly: best for people who want mistakes and tone flagged as they write, if 100 AI prompts a month is enough.
- QuillBot: best for people who rewrite short passages, if the 125-word cap fits their text.
How to run your own test
- Pick three real drafts. For example an email, a section of a report and a social post. Remove confidential details first.
- Define the job per tool. Ask assistants to edit and rewrite, and ask utilities to correct and adjust tone. Do not ask a utility to do an assistant’s job.
- Keep your instructions identical. Our guide on writing a brief that AI can follow helps.
- Use a rubric. Meaning preserved, tone right, no invented facts, effort to fix. Mark yes, partly or no.
- Log the limits. Note when a tool stops you or removes a feature.
- Check facts yourself. Follow how to check AI output for mistakes.
Decision checklist
- I know whether I need an assistant, a utility or both.
- I have compared the free limits against my real weekly volume.
- I know which features I need that are behind a paywall.
- I have read the data terms and set opt-outs.
- I have run the same drafts through each shortlisted tool.
- I know the first paid tier and what it adds.
Frequently asked questions
Which free AI writing tool is best?
We did not test writing quality, so we cannot name one. The right choice depends on your limits, features and data needs.
Is Grammarly’s free plan enough?
It lists 100 AI prompts a month and no full-sentence rewrites or tone adjustment. That suits light use; heavier users may hit the limit.
Can I use these tools without signing up?
Microsoft says Copilot does not require sign-in, though signing in adds features. Check the other tools’ current sign-up rules.
Do free tools keep my text?
They can. OpenAI says consumer content may be used for training unless you opt out. Read each tool’s data terms before pasting anything sensitive.
Will free tiers change?
Yes, often. Recheck limits before building a routine around one. Our guide on how to test an AI tool before you pay for it helps.
Conclusion
A fair comparison of free writing tools separates assistants from utilities, measures the limits against your real volume, checks the data terms and then tests with your own drafts. On the documentation we read, the clearest published numbers come from Grammarly and QuillBot, while ChatGPT and Claude describe their limits more loosely. Use how to choose an AI tool and how to compare AI tools side by side fairly alongside this guide, and verify details on each vendor’s site.
Sources
- OpenAI: ChatGPT free tier FAQ, accessed 11 November 2026
- OpenAI: How your data is used to improve model performance, accessed 11 November 2026
- Anthropic: Claude pricing, accessed 11 November 2026
- Microsoft Support: Copilot free and Copilot in Microsoft 365, dated 9 November 2026, accessed 11 November 2026
- Grammarly plans, accessed 11 November 2026
- QuillBot Help: Free vs Premium account, accessed 11 November 2026
- QuillBot Premium, accessed 11 November 2026
