# Grammarly vs ChatGPT for grammar and editing

A real-time checker and a general AI assistant, compared on how they check, what has been measured, and what each costs

By Artur Sapek. Published 2026-10-14. Updated 2026-10-14.

Summary

- Grammarly corrects your writing as you type across apps. ChatGPT proofreads and rewrites only when you ask, but it can take open-ended requests on whole passages.
- Grammarly is the better choice for real-time suggestions across supported apps and in its Docs workspace. ChatGPT is the better choice for open-ended editing requests in chat, Canvas, or Word.
- ChatGPT has the lower-priced paid tier. Grammarly Pro costs more but includes plagiarism and AI-text detection.

People compare these two because both now use AI to fix writing, and paying for both can seem unnecessary. They work differently by default. Grammarly runs in your browser, desktop, and phone and flags problems as you write. ChatGPT does nothing until you give it a prompt, and then it can proofread, rewrite, or restructure whatever you give it.

I have spent the past year building Revise, a word processor with an AI editing agent that is mentioned briefly near the end, and we run a public proofreading benchmark of AI models, including OpenAI’s. The plans below come from each vendor’s own pages, which are linked in the sources at the end.

## Grammarly vs ChatGPT at a glance

|  | [Grammarly](https://www.grammarly.com) | [ChatGPT](https://chatgpt.com) |
| --- | --- | --- |
| Free plan | Yes (100 AI prompts a month) | Yes (3 file uploads a day, 27K-token Instant context) |
| Paid from | $12/mo (Pro) | $8/mo (ChatGPT Go) |
| When it checks | As you type across supported apps, Docs agents also respond to prompts | When you ask, in chat, Canvas, or Word |
| How fixes appear | Underlines in supported apps, Docs agents suggest revisions | A corrected reply, inline suggestions in Canvas, or edits inside Word |
| AI models | Not disclosed | GPT |
| Inside Word | Yes (via the Grammarly desktop app) | Yes (ChatGPT for Word add-in) |

Table 1: Grammarly and ChatGPT compared on plans, when and how they check, models, and Word support.

## Key differences

These are the dimensions that matter most for grammar and editing work.

### Real-time vs on request

Grammarly checks while you type in Word, Google Docs, email clients, and websites, through its desktop apps for Windows and Mac, browser extensions, and mobile apps ([Grammarly for desktop](https://www.grammarly.com/desktop)). ChatGPT checks only what you paste, upload, or open in Canvas, or the Word document you ask about through the ChatGPT for Word add-in. Grammarly lists free spelling and basic grammar corrections in 23 languages and advanced suggestions in six ([Grammarly languages](https://www.grammarly.com/languages)). We found no comparable published count for ChatGPT.

Edge: Grammarly, because it catches mistakes before you send them.

### Proofreading accuracy

On [ErrataBench](https://revise.io/errata-bench), which seeds 99,000 words with realistic errors, GPT-5.6 Sol with medium reasoning fixed 96.5% and GPT-6 Sol with no reasoning fixed 95.4% ([full results](https://revise.io/blog/best-ai-model-for-proofreading)). The benchmark runs models in its own harness, not in the ChatGPT app, and the model ChatGPT uses depends on your plan and settings. Grammarly does not disclose its models and is not in the benchmark, so there is no number to compare directly.

Edge: neither. ErrataBench publishes results for specific OpenAI models and settings, but it did not test either app, so it cannot show which app is more accurate.

### Rewriting and restructuring

Grammarly Pro rewrites full sentences and adjusts tone, paid plans add full-paragraph rewrites, and 2,000 AI prompts a month cover drafting and replies. [Grammarly Docs](https://www.grammarly.com/docs) adds agents for proofreading, citations, and reader reactions. ChatGPT takes open-ended requests, so you can ask it to reorganize or rewrite a whole draft. In a test on one contract in [our document review test](https://revise.io/blog/ai-document-review-tools-compared), Grammarly’s document agent left comments that were mostly sentence-level, and ChatGPT gave thorough feedback but returned a new `.docx` without tracked changes.

Edge: it depends on how you work. Grammarly is better for guided edits inside its apps and Docs, and ChatGPT is better for open-ended requests.

### Word documents

Grammarly works in Word on Windows and Mac through its desktop app. ChatGPT reads uploaded `.docx` files on every plan, and the [ChatGPT for Word](https://help.openai.com/en/articles/20001526-chatgpt-for-word) add-in is available on every plan, subject to its usage limits, if your organization allows add-ins.

Edge: neither. Both work inside Word, but Grammarly checks continuously and ChatGPT checks when you ask.

### Price and extras

ChatGPT Go costs $8 a month (monthly billing, may include ads) and Plus costs $20. Grammarly Pro is $12 a month billed annually or $30 month to month, and it includes plagiarism and AI-text detection. Both have free plans with limits. For example, Grammarly Free includes 100 AI prompts a month, and ChatGPT Free allows three file uploads a day.

Edge: ChatGPT has the lower-priced paid tier, but Grammarly is the better choice if you need detection in the same plan.

## Which should you choose?

Choose Grammarly if

- you want mistakes caught as you type across supported apps and websites
- you want real-time grammar, clarity, and tone suggestions
- you need plagiarism or AI-text detection

Choose ChatGPT if

- you want a finished draft proofread or rewritten
- you want a lower-priced paid plan
- you also use AI for drafting and research

## What each costs

| Tool | Cheapest paid plan | Monthly | Per year | AI on that plan |
| --- | --- | --- | --- | --- |
| Grammarly | Pro (billed annually, $30 month to month) | $12/mo | $144 | 2,000 AI prompts a month |
| ChatGPT | ChatGPT Go (monthly billing, may include ads) | $8/mo | $96 | More messages, uploads, and memory than Free |

Table 2: Cheapest paid plan for one person, monthly and per year, and what AI that plan includes. US dollars before tax.

## Where Revise fits

Revise, which publishes this guide, is a browser word processor whose AI agent proofreads a whole document on request with a GPT, Claude, Gemini, or Grok model you pick and proposes text and formatting fixes as tracked changes. AI usage is limited by plan, and some models need a paid plan. It opens and exports Word files. Like ChatGPT, it checks when you ask rather than as you type, and it is a separate editor rather than a Word add-in.

## The bottom line

Use Grammarly for real-time checks while you write, and ChatGPT for open-ended edits on request.

Sources

Prices and plan details were checked against each vendor’s own pages on October 4, 2026. Prices are in US dollars as each vendor lists them, and some include local tax. Vendors change plans often, so confirm on the linked page before you buy.

- Grammarly: [Usage and document limits](https://support.grammarly.com/hc/en-us/articles/115000090911-What-are-the-limitations-when-using-Grammarly), [Languages](https://www.grammarly.com/languages), [Desktop app](https://www.grammarly.com/desktop), [Browser extension](https://www.grammarly.com/browser), [Grammarly Docs](https://www.grammarly.com/docs), [Plans](https://www.grammarly.com/plans), [Grammarly for Word](https://www.grammarly.com/microsoft-word)
- ChatGPT: [Pricing](https://chatgpt.com/pricing), [Free tier FAQ](https://help.openai.com/en/articles/9275245-chatgpt-free-tier-faq), [File uploads FAQ](https://help.openai.com/en/articles/8555545-file-uploads-faq), [Writing blocks](https://help.openai.com/en/articles/20001246-working-with-writing-blocks-and-code-blocks-in-chatgpt), [ChatGPT for Word](https://help.openai.com/en/articles/20001526-chatgpt-for-word), [Capabilities overview](https://help.openai.com/en/articles/9260256-chatgpt-capabilities-overview), [ChatGPT for Word](https://help.openai.com/en/articles/20001526-chatgpt-for-word), [Creating documents with ChatGPT Work](https://help.openai.com/en/articles/20001278-creating-and-editing-documents-spreadsheets-and-presentations-with-chatgpt-work), [Google Drive app](https://help.openai.com/en/articles/10929079-google-drive-app-and-setup-in-chatgpt), [Google app data controls](https://help.openai.com/en/articles/10408842-google-app-data-controls-faq), [Supported file types](https://help.openai.com/en/articles/8983675-what-types-of-files-are-supported), [ChatGPT for Google Sheets](https://workspace.google.com/marketplace/app/chatgpt/870214997678)

## Frequently asked questions

### Is ChatGPT better than Grammarly for grammar?

They do different jobs. Grammarly corrects as you type across apps. ChatGPT proofreads on request, and OpenAI's GPT-5.6 Sol with medium reasoning fixed 96.5% of seeded errors on the ErrataBench proofreading benchmark, which tests models rather than the ChatGPT app. Grammarly is not in that benchmark, so there is no direct accuracy comparison.

### Can ChatGPT replace Grammarly?

ChatGPT can do a final proofreading pass when you ask, but it does not replace Grammarly's continuous checking across supported apps. Whether it is enough depends on whether you need review on request or real-time suggestions.

### Which is cheaper, Grammarly or ChatGPT?

ChatGPT has the lower-priced paid tier. Its cheapest paid plan, Go, is $8 a month and may include ads, and Plus is $20. Grammarly Pro is $12 a month billed annually or $30 month to month. Both have free plans with limits.

### Can I use Grammarly and ChatGPT together?

Yes. You can use Grammarly while you type and then use ChatGPT for a larger edit of the finished draft.

### Do Grammarly and ChatGPT work in Microsoft Word?

Yes. Grammarly works in Word on Windows and Mac through its desktop app. The ChatGPT for Word add-in is available on every ChatGPT plan, subject to its usage limits.