Grammarly, QuillBot or Claude for Business Writing: Which to Use

You have a proposal due this afternoon and it reads badly. Or a customer email that needs to sound firm without sounding cross. Or a page of website copy that three people have edited until it says nothing. You open a writing tool and find three different kinds of product that all say they "improve your writing".

They are not the same job. One fixes what you wrote as you type. One rewrites a sentence in a different voice. One drafts from a blank page and can work through a long document with you. Pick the wrong one and you either fight the tool or pay for features you never touch.

This guide covers three tools we review on Find AI Now: Grammarly, QuillBot and Claude. It draws on our reviews, each vendor's own pages, and the Australian privacy regulator's guidance on putting text into AI tools. Sources are at the end.

Quick answer: use Grammarly if you want your own writing checked for grammar, tone and clarity wherever you type. Use QuillBot if the job is rewording a passage you already have. Use Claude if you want a first draft, a rewrite of something long, or help working through a document. Many small businesses end up with one checker and one assistant. Before any of them sees customer details, read what the vendor does with your text.

Three jobs, not one

Business writing breaks into three jobs, and the tools split along them.

Editing. You wrote it. You want typos, grammar and tone caught as you go, in the email or document where you are already working. The tool should be quiet and sit inside your other apps.

Rewriting. You have text and you want it said differently: shorter, plainer, a different register, or reworded so it does not echo the source. The tool takes a passage and returns options.

Drafting. You have an idea, some notes or a long document. You want a first version, a summary, or a conversation about what is missing. The tool needs room to take a lot of context and answer in full.

Grammarly: editing where you already write

Grammarly is built for the editing job. Its own site says it works in desktop apps, browser extensions, Microsoft Office, Google Docs and mobile apps, so the suggestions appear in the email or document you are in. It checks grammar and clarity, suggests tone changes, and has AI tools for rewriting and generating text.

Our review says it is good for fixing grammar, tone and clarity wherever you type. It is the one to pick when the problem is polish, not ideas.

What the plans gate matters. On the vendor's plans page, the free plan covers basic writing checks and shows you your tone, but adjusting tone, full-sentence rewrites, plagiarism checks and AI-text detection sit on the paid plans. AI prompts are capped on every plan except the top one. Team features such as shared style guides and roles are on paid plans too.

The catch, from our review: AI prompts are capped by plan, and its privacy policy describes using your text to improve its AI, with an opt-out in your account settings. The vendor's own site also says it does not sell user content and does not let third-party providers train their models on it. Both can be true. Find the opt-out and decide before staff install it on machines that handle customer emails.

Skip it if you need plagiarism checks or full rewrites on the free plan.

QuillBot: rewording what you have

QuillBot started as a paraphraser and still centres on that. The vendor lists a paraphraser, grammar checker, summariser, translator, plagiarism checker and AI detector, with a browser extension, a Word add-in and apps. It is aimed at students, professionals and business owners alike.

Our review says it is good for paraphrasing, grammar checking and summarising text. For a small business that is the passage that came out clumsy, the supplier description you want in your own words, or a long report you need cut to a paragraph.

On the vendor's Premium page, the paid plan lifts the word limits on paraphrasing and summarising, adds more paraphrasing modes, and opens the plagiarism checker and translation. The free plan is a taste of that.

The catch, from our review: the free paraphraser limits text length and modes, the plagiarism checker is Premium only, and the AI detector's accuracy varies by test, so never rely on it alone for academic or career decisions. The same goes for a business decision about a contractor's or applicant's writing. A detector score is a prompt to talk to someone, not a verdict.

Skip it if you need long rewrites on the free plan. For rewording, always reread the result. A paraphraser can keep the words smooth and change the meaning.

Claude: drafting and working through long text

Claude is a general assistant, not a writing checker. It sits in the drafting job. You give it notes, a brief, or a long document, and ask for a first version, a summary, a tighter edit or a list of what is missing. You can then push back and ask for another pass.

Our review says it is good for writing, analysis and coding with long documents. That fits proposals, policies, tender responses and reports, where the problem is structure and not commas.

Anthropic's pricing page says every plan has usage limits that reset on a rolling session window, and paid plans add weekly limits on top. Features such as sharing projects with colleagues and admin controls sit on the team plan. It also says model training on your content is opt-out on the free and individual paid plans, and off by default on the team plan.

The catch, from our review: paid plans cap usage in rolling windows, so heavy users can hit limits and need a higher tier. Skip it if you want image generation built in, or heavy daily use on a free plan.

Claude will not sit inside every email box the way a checker does. You move text to it and back. That is fine for a proposal and tiresome for forty short replies a day.

The question that matters more than the tool: your text

All three tools take what you write and send it to a vendor's servers. The Office of the Australian Information Commissioner says that entering personal information into an AI system is a use or disclosure under the Privacy Act, and recommends, as best practice, not entering personal information into publicly available AI tools. It also tells organisations to check whether the developer can use your inputs for training, and to turn that off where they can. Its guidance was updated in January 2025, so read the current page, not a summary of it.

In practice:

• Remove names, contact details and account numbers before pasting, or use a paid plan whose terms say your content is not used for training.
• Check the setting on each tool. The opt-out is rarely on by default.
• Write down which tool your team may use for what. Our post on writing an AI use policy for a small team is one page of that.

How to choose

Ask what is actually wrong with the writing.

• It is correct but sounds off, or is full of small errors. Grammarly.
• It says the right thing in the wrong words. QuillBot, or Claude if the passage is long.
• There is nothing on the page yet, or there is too much of it. Claude.
• You write to customers all day. Grammarly for the checking, and Claude when a reply needs thought.

Start on the free plan of whichever fits, use it for a week on real work, and pay only for the limit you actually hit.

Where to start

• Put the three side by side on the compare page, with features and plans in one view.
• Browse the writing enhancement tools we review if none of these three fits.
• If you want help choosing for a team, ask the Concierge.

Sources

• Grammarly home page and plans page, read 22 October 2026.
• QuillBot home page and Premium page, read 22 October 2026.
• Anthropic, Claude pricing page, read 22 October 2026.
• Office of the Australian Information Commissioner, Guidance on privacy and the use of commercially available AI products, published 21 October 2024, updated 17 January 2025.
• Find AI Now "Our take" reviews of Grammarly, QuillBot and Claude, reviewed 10 October 2026.