Grammar checkers and writing assistants: where they help and where to stop

Writing assistants now go well beyond spelling: they suggest tone, rewrite whole sentences and, in some cases, generate text from a prompt. That makes them more useful, and it also makes it easier to cross a line your instructor cares about. Here is what the main tools do, where they fit in the writing process, and how to use them without handing over your own voice.

Where a checker fits in the writing process

The first thing to know is when to use one. The Writing Center at the University of North Carolina at Chapel Hill separates three jobs. Revision is rethinking the paper: the argument, the evidence, the structure. Editing is improving the wording. Proofreading, fixing grammar, spelling and punctuation, comes last.

A grammar checker is a proofreading and editing tool. It cannot tell you whether your thesis is weak or your paragraphs are in the wrong order, and polishing sentences in a draft whose argument does not work is wasted effort. Revise first, then run the checker.

The main tools

Grammarly’s free plan checks for mistakes and shows the tone of your writing, and includes a limited number of AI prompts; the paid plan adds full-sentence rewrites and more AI prompts. Beyond grammar, its tools include tone suggestions, a plagiarism checker and a citation generator. It works in Google Docs and Microsoft Office, as an extension for Chrome, Safari, Firefox and Edge, and in apps for Windows, Mac, iPhone, iPad and Android.

Microsoft Editor is Microsoft’s AI-powered checker, working in more than 20 languages. It underlines the problems it finds and you choose whether to accept or ignore each suggestion. It runs as a browser extension for Edge and Chrome and in Word and Outlook. The free version covers the basics of grammar and spelling; with a Microsoft 365 subscription it adds suggestions on clarity, conciseness, formality and vocabulary.

LanguageTool is an AI-based grammar checker with a wide language range: English, German, Portuguese, Spanish, French and Dutch, plus more than 30 other languages and dialects. That makes it a strong choice for students who write in more than one language. It has add-ons for Chrome, Edge, Firefox and Opera, and plugins for Google Docs, Word, Apple Pages and LibreOffice.

ProWritingAid combines a grammar checker with detailed writing reports on your style. It is aimed mainly at fiction writers, with tools for analyzing plots and manuscripts, and it connects to Google Docs and Microsoft’s apps. Its makers state that it will never write your work for you.

QuillBot is best known for its Paraphraser, which rewords text you paste in, and it also offers a grammar checker, a summarizer, a translator and a citation generator. Clemson University’s Writing Lab notes that a summary generated this way is easy to spot in your writing unless you rework it into your own voice; otherwise it reads abrupt and lifeless.

Hemingway Editor focuses on readability: making writing correct and clear. It offers a free online readability checker, and the paid Hemingway Editor Plus adds grammar checking and tone adjustment, with a two-week free trial.

Correcting is not the same as writing

The honest-use question comes down to how much of the text is still yours. Accepting a fix for a misplaced comma or a misspelled word is proofreading. Accepting a rewrite of a whole sentence or paragraph is different: the words are now partly the tool’s. Generating text from a prompt is different again.

Paraphrasing tools need particular care. The University of North Carolina at Chapel Hill’s Writing Center defines paraphrasing as putting another person’s ideas into your own words, and says that changing a word or two in someone else’s sentence, rearranging its structure while keeping the original words, or swapping in a few synonyms is writing too close to the original: that is plagiarizing, not paraphrasing. Running a source through a rewording tool does exactly those things, so it does not turn someone else’s sentence into yours, and the idea still needs a citation.

Policies vary. Cornell University’s Learning Strategies Center points out that every class and every instructor sets different expectations about AI, and that it is your responsibility to know them and to ask if you are unsure. Treat the generative features of a writing assistant, such as full rewrites and text from prompts, as AI use under your course’s policy, not as spell-checking.

Some universities spell the rule out. Clemson University’s academic integrity statement says that work generated with artificial intelligence and turned in without attribution is plagiarism.

Where AI use is allowed, be open about it. The MLA Style Center says to acknowledge functional uses of generative AI, such as editing your prose or translating words, in a note or in your text.

Keep your own voice

There is also a quality argument for restraint. Cornell’s center notes that AI is good at producing boilerplate, and you may not want your writing to sound like boilerplate. Suggestions tuned for clarity can flatten a distinctive phrase or change a meaning you chose carefully. Read every suggestion before accepting it, reject the ones that change what you meant, and treat the checker as a second pair of eyes rather than a co-author.

A good routine: write and revise the draft yourself, run the checker once the argument is settled, decide on each suggestion one at a time, and then read the final version through once more yourself.