QuillBot vs Grammarly: Paraphraser or Proofreader for Academic Writing?

Grammarly proofread the test paragraph more accurately than QuillBot. It flagged that "LNP delivered" needs a hyphen, where QuillBot's Grammar Checker offered to add "and", which would leave the sentence without a main verb. QuillBot is the one to open for references, because its Citation Generator turned the trial's title into a complete reference in one click.

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TLDR: QuillBot or Grammarly?

Proofread the paper in Grammarly. On the same paragraph it caught the missing hyphen that QuillBot misread, and it exports the edited file to Word or PDF. Reword and build references in QuillBot, where Fluency kept the trial result intact and a title search produced the NEJM paper's APA 7th entry in one click.

How the two were tested

Each tool got the same paragraph and the closest matching feature for each job.

• Same paragraph - a 201-word passage about lipid nanoparticles carrying CRISPR-Cas9 to the liver, typed into a new document in each tool.

• Errors put there on purpose - "There is a lot of things that still needs" and "could perhaps maybe". The paragraph also leaves four compound adjectives unhyphenated: "E mediated", "LNP delivered", "long term" and "off target".

• One number to keep - a mean 87 percent fall in serum transthyretin at the higher dose (Gillmore et al., NEJM 2021). The PubMed abstract reports 87 percent at 0.3 mg per kilogram and 52 percent at the lower 0.1.

• Matched features - QuillBot's Grammar Checker against Grammarly's Proofread panel, the two paraphrasers against each other, and the two citation generators.

• Logged as it happened - every card title, rewrite and timing was taken from the screen at the time.

The same paragraph in both

The rewrite: did the claims keep their strength?

QuillBot - the Paraphraser took the middle three sentences, 96 words in all, in Fluency mode. The trial sentence came back whole: "The first in-human systemic trial of LNP-delivered CRISPR therapy found an 87 percent mean reduction in serum transthyretin at the higher dose after a single infusion."

Its version of the clunky sentence ran to 35 words, down from 43, and the hedge kept "It is possible that" with "main" turned into "primary": "It is possible that ionizable lipid chemistry is the primary mechanism for extrahepatic targeting, but this has yet to be demonstrated conclusively."

Grammarly - the Paraphraser agent opens with a reading of the text: "Your scientific summary is informative and objective, but the tone could be more concise and confident in its assertions." Academic is one of its styles, and that run covered the whole paragraph.

The rewrite appeared within 8 seconds under the heading "Eliminate hedging, clarify challenges, and formalize tone". The trial sentence kept "mean", "87 percent" and "at the higher dose", and gained the hyphen in "LNP-delivered".

The clunky sentence came down to 25 words: "However, several challenges remain, including understanding particle behavior outside the liver, assessing immune responses to repeat dosing, and evaluating long-term editing outcomes at off-target sites."

Grammarly's hedge swapped "It is possible that" and "could perhaps maybe" for a single "may": "Ionizable lipid chemistry may serve as a key factor for extrahepatic targeting, although this has not been conclusively demonstrated."

Two meanings moved in Grammarly's version. "The main lever" became "a key factor", and the closing clause about the gap preclinical work is trying to close became "the primary focus of ongoing preclinical research".

Winner - QuillBot, on keeping each claim as strong as the paragraph made it: Fluency kept "main" as "primary", while Grammarly's Academic run turned "the main lever" into "a key factor".

<ProTip title="🔍 Check the claim strength:" description="Compare each hedge in a paraphrase with the original. One rewrite here turned the main lever into a key factor, a weaker claim than the paragraph made" />

The proofread: one card that breaks a sentence

QuillBot - the Grammar Checker opens a document editor. It detected English (AU) and, within 27 seconds of the typing stopping, listed 12 grammar corrections with an Accept all button and scores of Grammar 85, Fluency 49, Clarity 57 and Engagement 93.

Nine of the 12 cards fixed real faults: agreement, the hyphens in E-mediated, long-term and off-target, the punctuation, and the extra "maybe". Two were regional spellings from the detected language, "per cent" and "ionisable".

The remaining card, card 3, proposed "therapy and reported" in place of "CRISPR therapy reported". Accept all applied it with the rest, and the scores rose to Grammar 100 and Excellent over a trial sentence with no main verb.

QuillBot after Accept all: the trial sentence now reads therapy and reported, and has no main verb.

Grammarly - within 8 seconds of the paragraph going in, the Proofread panel showed a writing quality of 60 and 16 suggestions: 10 under Grammar and 6 under Clarity.

• Spelling cards - "LNP delivered" to "LNP-delivered", plus cards on E mediated, long term and off target.

• Agreement and punctuation - "is" and "needs", then the punctuation at "circulation", "though" and "example".

• The hedge - a Rephrase card that removes "maybe" and leaves "could perhaps be", the same result QuillBot gave.

• Clarity - six "Improve your text" cards, one for each sentence of the paragraph.

Grammarly Proofread: the Correct your spelling card, LNP delivered to LNP-delivered.

The hyphen is the fix the trial sentence needed: "LNP-delivered" makes it a compound adjective, and "reported" stays the verb.

The Clarity card for the clunky sentence offered a 38-word rewrite: "There are still many things that need to be worked out, for example, how the particles behave outside the liver, whether repeat dosing causes an immune response, and what the long-term editing outcomes look like at off-target sites."

Winner - Grammarly, on the error that matters most in a results sentence: it proposed the hyphen in "LNP-delivered", where QuillBot's card would have removed the main verb.

<ProTip title="🧭 Set the dialect:" description="Choose the English variety in the language menu before a check. Automatic detection picked Australian English here and turned percent into per cent" />

The reference: a search box against a form

QuillBot - the Citation Generator takes a title, DOI, URL or ISBN and formats in "over 1,000 different styles". A search on the trial title listed 20 results, the 2021 NEJM paper at the top and the 2022 reprint below it.

One click built the entry. It lists 19 authors, then an ellipsis, then the final author, as APA 7th requires for 21 or more authors, followed by the journal details and the DOI.

The title printed "CRISPR-CAS9" for "CRISPR-Cas9", and the umlaut in "Täubel" was dropped. The Suggestions tab still read "All good! We've identified no suggestions to improve or clarify your citation."

QuillBot reference list: the CRISPR-CAS9 title and a Suggestions tab reading All good.

Grammarly - the Free Citation Generator is a form. It offers APA, MLA and Chicago, 14 source types, and fields for each contributor, the year, title, publisher, pages, DOI and URL, all typed by hand.

Inside a Grammarly document, the Citation Finder agent works the other way round. It read the paragraph, marked three claims and, for the trial sentence, listed nejm.org first with the NEJM DOI. This test did not insert that citation, so its formatted entry is not reported here.

QuillBot's nearest match is its AI Chat with web search. Asked for the source of the same sentence, it named a Regeneron press release from June 2021 and wrote an APA entry for that, with the dose right and no DOI.

Winner - QuillBot, on a complete reference entry from a title in one click. Grammarly's form needs every author typed by hand.

The file: what leaves the editor

QuillBot - the document editor's menu holds Preferences, Clear text, Give feedback and Move to trash, with a copy icon on the toolbar and no export item. Export lives in the other tools: an Export icon under each summary, and Export to Word in the reference list menu.

Grammarly - the document menu has Print & export, with Print, Export to PDF and Export to Word (.docx). Nothing was downloaded in the test.

Winner - Grammarly, on getting the edited document out: Word or PDF from the editor menu.

<ProTip title="🖨️ Plan the export:" description="Check how the final file will leave each tool before deadline week. Grammarly exports the document, while QuillBot exports summaries and reference lists" />

Where each one works

QuillBot is a set of separate pages, one per tool, listed in a sidebar menu. A Paraphrase Summary button links the Summarizer to the Paraphraser, and QuillBot’s site lists a Word add-in next to its browser and phone apps.

Grammarly puts one document in the middle and a rail of agents beside it. The writing agents on that rail:

• Paraphraser - Academic, Professional, Streamlined and Creative styles, or a style described in words.

• Citation Finder - finds sources for claims and offers to insert an in-text citation.

• Reader Reactions and AI Grader - feedback on how a reader might take the text, and rubric-based feedback with an estimated grade.

QuillBot has a dedicated Summarizer, which Grammarly's rail does not. On the test paragraph it returned 104 words from 201 and kept the 87 percent, but dropped "mean" and "at the higher dose". QuillBot's site also lists paraphrasing in 23 languages and translation into 40+.

Grammarly marks the claims that need a source by itself, where QuillBot's nearest match is asking AI Chat. Reader feedback has no counterpart among the QuillBot tools tested.

What each one costs

US list prices from each company's own pages: one month, three months and a year.

October 2026 pricing, from quillbot.com/premium, QuillBot’s price page, grammarly.com/plans and Grammarly’s Pro pricing help page.

QuillBot costs less on every cycle: $44.05 less over a year. Grammarly Pro adds full-sentence rewrites, tone adjustment and 2,000 AI prompts a month; QuillBot Premium adds every paraphrase mode and 6,000-word summaries.

Using both on one paper

The two cover different stages, so one paper can use both in this order:

• Proofread in Grammarly - card by card, with the language set first, and every figure checked after each accepted rewrite.

• Reword in QuillBot - background sentences only, in Fluency, compared line by line with the original.

• Build references in QuillBot - from each source's title, then open each DOI to check capitals, gene names and accents.

• Export from Grammarly - to Word or PDF once the text is final.

<ProTip title="📌 One more option:" description="If the paper is still being drafted, Jenni searches papers at the cursor and files the reference as you cite, so the text and the reference list never separate" />

Which one should a postgraduate pay for?

Grammarly, if one tool has to check the language of a thesis or manuscript: it caught the fault that mattered and exports the edited file. QuillBot, if the work is mostly rewording and references and the budget is $99.95 a year, with Fluency mode and the Citation Generator doing the useful work.

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The full QuillBot review covers its Summarizer and AI Chat on the same test material.

If the paper is still being written, the citing can happen in Jenni at the cursor, with Claim confidence checking each claim and export to Word or LaTeX at the end. Either tool can still do a final pass, and more comparisons are in the tool reviews.