- Which job are you hiring a writing assistant for?
- What each tool is built to do
- Grammarly and QuillBot side by side
- Using them in real writing situations
- Privacy and data use: what to read before you paste anything
- School, university and publisher rules on AI
- A simple test before you pay
- Mistakes to avoid with any writing assistant
- Choosing between the two
- Frequently asked questions
Grammarly is mainly a checker for spelling, grammar, clarity and tone as you write. QuillBot started as a paraphraser and added grammar, summarising and translation tools. Both have free plans, so test each on your own writing and read the privacy settings before you pay.
People often search for Grammarly and QuillBot as if they were rivals, and they do overlap. Both check your writing, both run in a browser and both now have AI features. But they began with different jobs. Grammarly grew up as a checker that sits alongside your writing and flags mistakes, tone and clarity. QuillBot grew up as a paraphraser that rewrites sentences, then added a grammar checker and other tools around it. This comparison draws on each company's own product, plan and help pages rather than a long personal trial, so it focuses on what to look for and what to check before you pay for anything.
Which job are you hiring a writing assistant for?
| If your main need is | You may lean towards | Why |
|---|---|---|
| Catching mistakes in emails, proposals and posts as you type | Grammarly | Checking as you write is its core job |
| Changing the tone of a message before it goes out | Grammarly | Tone suggestions are a headline feature |
| Rewording a clunky paragraph in several styles | QuillBot | The paraphraser is where it started |
| Shortening a long article or report into key points | QuillBot | It has a dedicated summariser |
| Writing in English as a second language | Either | Both offer grammar help, so compare the suggestions on your own text |
| A team that needs one tool everyone uses | Check both | Look at team plans, admin controls and data settings |
Notice that the first two rows and the next two rows describe different habits. Checking is something you do to your own sentences. Paraphrasing is something you do to a passage you want worded differently. Plenty of people end up wanting a bit of both.
What each tool is built to do
Grammarly
Grammarly's plan page describes a free tier with core spelling and grammar checks and tone visibility, plus a monthly allowance of AI text-generation prompts. Its paid tier adds full-sentence rewrites, adjustable tone, help with fluent English, inclusive language suggestions, consistent citation formatting, and detection of AI-generated text and accidental plagiarism. It also lists team features such as snippets and shared knowledge.
QuillBot
QuillBot's help centre explains that its paraphraser gives free accounts two modes, Standard and Fluency, with Premium unlocking all nine modes plus custom modes. Free users can paraphrase a limited number of words at a time, with no cap on Premium. Around the paraphraser it offers a grammar checker, a summariser, a translator, an AI detector and a plagiarism checker, and the help centre describes some of those as Premium features. Limits and inclusions change, so check the plan page for the tool you care about.
Grammarly and QuillBot side by side
| Area | Grammarly | QuillBot |
|---|---|---|
| Core job | Spelling, grammar, clarity and tone while you write | Paraphrasing and rewording, with a grammar checker alongside |
| Free plan | Yes, with core checks and a limited AI allowance | Yes, with limits on paraphrasing and some tools |
| Tone suggestions | Yes, adjustable on the paid tier | Paraphraser modes change style, such as formal or fluent |
| Plagiarism checking | On paid plans, per its plan page | Described in its help centre as a Premium tool; confirm current terms |
| AI text detection | On paid plans, per its plan page | An AI detector tool, with free limits stated on its own page |
| Summarising | Not its focus | Dedicated summariser |
| Translation | Not its focus | Translator tool |
| Where it works | Windows and Mac apps, Chrome, Safari, Firefox and Edge, Microsoft Office, Google Docs, iPhone, iPad and Android | Chrome extension that works in Google Docs when you're logged in, and a Word add-in |
| Team options | Business and enterprise plans | A team plan, per its help centre |
Treat the table as a checklist for your own research. Both companies keep changing what each plan includes, and the plan page is the only place to confirm it.
Using them in real writing situations
- A client proposal. A checker that catches typos and tone slips as you go is more useful than a rewriter that changes your meaning.
- A paragraph that reads like a robot wrote it. A paraphraser can offer several rewordings, but you still need to read each one and keep your own voice.
- A long report for a busy boss. A summariser can produce a first pass; always check it against the original.
- A newsletter or blog post. Run a checker last, after you've written and edited by hand.
- An email to a customer who's upset. Tone suggestions can help, but a human read-through matters more than any tool.
If you want a wider look at the field, my guide to the best grammar checkers for business compares more options, and how Grammarly built its brand is worth a read if you're curious why it became so familiar.
Privacy and data use: what to read before you paste anything
Anything you type into a writing assistant travels to a server, so it's worth ten minutes with each company's privacy pages, especially if you handle client work.
Grammarly's privacy FAQ says it may use random samples of aggregated and de-identified content to improve its service unless you opt out, and its trust centre points to a Product Improvement and Training setting in your account. It also says it doesn't allow its AI providers to train on user content, and that some account types are excluded automatically. Its pages aren't perfectly consistent with each other, so read the current policy rather than relying on a summary like this one.
QuillBot's help centre says inputs and usage data may be used to improve and personalise its service, with controls to opt out of storing your text and of using it for model training. It says it doesn't train on text from team plan users, and doesn't sell your content. Again, the help centre is the place to confirm the current position for your account type.
My practical rule: don't paste anything confidential, such as unreleased financials, a client's personal details or a contract under negotiation, into any consumer writing tool until you've checked the data settings and, where needed, your client's rules.
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School, university and publisher rules on AI
Rules differ widely. Some schools and universities allow grammar checkers but not paraphrasing or AI rewriting; some publishers and clients ask you to declare AI use; others ban it. A grammar fix and a full rewrite are not the same thing in many policies. If you're a student, read your institution's academic integrity policy and ask your tutor if it's unclear. If you write for a publication or client, ask for their AI policy in writing. Neither tool can tell you what your institution or client will accept.
A simple test before you pay
- Pick three pieces of your own writing: a short email, a longer article and something awkward you've been avoiding.
- Run all three through the free plan of each tool.
- Note which suggestions you'd accept without thinking and which change your meaning.
- Check that the extension works where you write, such as Gmail, Google Docs, Word or your content tool.
- Read the privacy settings and switch off anything you don't want.
- Open the plan page and confirm that the feature you want, such as plagiarism checking or tone control, is on the plan you're considering.
- Use the free plan for a couple of weeks before deciding whether a paid plan earns its place.
Mistakes to avoid with any writing assistant
- Accepting every suggestion. The tool doesn't know your audience.
- Using a paraphraser on someone else's work and passing it off as your own.
- Letting tone suggestions flatten your personality. Your voice is part of why people hire you.
- Trusting AI-detection scores as proof of anything; they can be wrong in both directions.
- Forgetting that a tool can't fact-check your claims.
Choosing between the two
If you write a lot of emails, proposals and posts and want a safety net that catches slips as you go, a checker-first tool is the natural fit. If your pain is rewording, summarising or translating text, a paraphraser-first tool is closer to what you need. If you're not sure, start on the free plan of both, use them side by side for two weeks and keep whichever one you open without reminding yourself. And remember that no tool replaces reading your work aloud before you send it.
Make an AI writing or editing tool? See how to get it featured on this list.
Frequently asked questions
Is QuillBot the same as Grammarly?
No. Grammarly is mainly a checker for spelling, grammar, clarity and tone while you write. QuillBot started as a paraphraser and added a grammar checker, summariser, translator and other tools.
Do Grammarly and QuillBot have free plans?
Yes, both do, according to their own sites. Grammarly's free plan covers core spelling and grammar checks with a limited AI allowance, and QuillBot's free plan limits paraphrasing modes and some tools. Check each plan page for current limits.
Which one is better for a student?
It depends on your institution's rules. Many allow grammar checking but restrict paraphrasing or AI rewriting, so read your academic integrity policy and ask your tutor before relying on either.
Do they check for plagiarism?
Grammarly lists plagiarism detection among its paid features. QuillBot has a plagiarism checker that its help centre describes as a Premium tool. Confirm what's included on the current plan page.
Do Grammarly and QuillBot use my writing to train AI?
Both describe settings for this. Grammarly refers to a Product Improvement and Training control, and QuillBot describes opt-outs for storing and training on your text. Read the current privacy pages and adjust your account settings.
Can I use both together?
Yes. Some writers use a checker for final proofreading and a paraphraser or summariser for specific passages. Just make sure each suggestion still says what you mean.
