Which AI Writing Checker Is Worth Paying For as a Manager

Grammarly is the one worth keeping open, because its free plan already does most of the job: it catches grammar mistakes and flags a tone that will come across wrong before you hit send. Pay only if you write long documents every day. QuillBot, Wordtune, LanguageTool and ProWritingAid each win in situations Grammarly does not cover, laid out below.

What does each free plan fix?

Each free plan fixes a different problem, and the caps show what the vendor expects you to tolerate without paying. Grammarly’s free tier checks spelling and grammar, shows your writing’s tone, and includes 100 AI prompts a month, with no rewrite button and no tone adjustment, according to Grammarly’s own pricing page checked in October 2026. LanguageTool’s free plan checks up to 2,000 characters per text box and allows three AI rephrases a day, per LanguageTool’s premium page. QuillBot’s free paraphraser stops at 125 words per rewrite and offers only two modes, Standard and Fluency, according to QuillBot’s help center. Wordtune gives 10 free rewrites a day and three AI summaries a month, per its pricing page. ProWritingAid caps free checks at 500 words, with 10 rephrases, two line-editing reports and three sparks a day, listed on its pricing page.

How do the five compare?

Here is every dimension side by side, pulled from each vendor’s own page in October 2026. I used the same side-by-side method on meeting notetakers in Otter, Fireflies, Fathom or Granola; this is that method applied to writing checkers.

Which one rewrites best?

Grammarly’s rewrite only appears once you pay for Pro, and it works on a full sentence at a time, trading your original phrasing for a cleaner one while leaving the tone choice to you. QuillBot is built around rewriting first: free users get the Standard and Fluency modes, and Premium adds seven more, including Formal and Academic, according to QuillBot’s own help center. Wordtune reads closer to a second opinion on one sentence than a full redraft, which fits a quick Slack reply better than a long memo. ProWritingAid’s rephrasing tool lets you dial formality and length, useful for turning rough notes into a review document. LanguageTool’s paraphrasing sits behind Premium entirely, and reads more like a grammar engine with a rewrite feature attached than the reverse, per its premium page.

Where does your text go?

Every one of these tools processes your writing on a server you do not control, so what happens to it afterward is worth checking before you paste anything confidential. Grammarly trains its AI models on your content by default and lets you turn that off under Product Improvement and Training in account settings, while stating plainly that it does not sell or monetize your content, according to its trust page. QuillBot began storing text inputs by default for all users in a November 2025 policy change, with separate opt-outs for storage and for model training. Wordtune sends your text to its own servers and says staff access to documents is restricted to a small team fixing account problems, per its FAQ. LanguageTool says text typed into its browser add-on is usually not saved, while documents kept in its editor are. ProWritingAid states it never keeps anything you type into its editor.

Does it work on your phone?

Grammarly and QuillBot are the only two with a phone app; the other three live in a browser tab or desktop editor. Grammarly offers iPhone, iPad and Android apps alongside its browser and Office tools, per its plans page. QuillBot has a free keyboard app for both iOS and Android, according to its help center. Wordtune has an iOS app but nothing for Android, per its own site. LanguageTool offers an iPhone and iPad app with a system keyboard and a camera scan feature, but no official Android app, per its own post about the app. ProWritingAid has no phone app; its help center directs mobile users to a browser-based web editor instead, per its help center. For a manager replying to messages between meetings, that difference changes which tool you reach for first.

Five free plans, ranked by coverage

1. Grammarly covers the most ground for free: grammar, spelling and tone detection across a browser extension, Word, Google Docs and three mobile platforms.
2. LanguageTool checks grammar, spelling and punctuation with no word-count cap beyond 2,000 characters per box, plus three free rephrases a day.
3. Wordtune gives the most free rewrites of the five, 10 a day, though its grammar checking is lighter than Grammarly’s or LanguageTool’s.
4. ProWritingAid packs the most features into its free plan at once, line editing, rephrasing and creative nudges, but caps every check at 500 words and skips mobile entirely.
5. QuillBot is the most restrictive on the desktop side: 125 words per paraphrase and two of nine rewrite modes, though its mobile app is stronger than most of the others here.

When should you skip Grammarly?

Skip Grammarly when your writing is long-form rather than a quick message: ProWritingAid’s style reports go deeper into pacing and repetition across a whole document, and it states plainly that it never keeps what you type into its editor, according to its pricing page. Skip it when cost is the deciding factor: QuillBot’s annual plan runs $8.33 a month, cheaper than Grammarly’s $12-a-month average on an annual Pro plan, according to QuillBot’s own pricing page and Grammarly’s support page. Skip it if you write for readers in several languages, since LanguageTool’s own site states it supports over 30 languages, more than Grammarly lists on its page, per LanguageTool’s language list. And skip it if one sentence is all you need fixed: Wordtune’s rewrite box opens faster for that single job than Grammarly’s full editor does.

What should a manager do today?

Start with Grammarly’s free plan in your browser, in Word or Google Docs, and on your phone, since the tone check alone catches the message that reads harsher than you meant before a direct report sees it. If you draft one long document a month, a performance review or a strategy memo, test ProWritingAid’s free plan or QuillBot’s free paraphraser against that one document before paying for either. Move to a paid plan once you can name a specific weekly task the free tier cannot finish, not because an upgrade banner asked you to. Grammarly’s 100 free AI prompts a month are for its separate generative-writing feature, not the grammar checker; if those prompts keep returning generic text, the fix is usually adding constraints, covered in three lines that fix lazy AI answers. And if a manager above you questions whether AI helped write something, that is a separate conversation worth having directly, covered in how to explain AI-assisted work to a skeptical boss.

You are a blunt, practical communication coach helping a manager review a work message before it's sent. I will paste a message I'm about to send to my team or a colleague. Read it only for tone, not grammar. Point out any specific phrase that could come across as harsh, passive-aggressive, or unclear to someone who can't hear my intent, and suggest one plain alternative for each flagged phrase. If the message reads fine as is, say so plainly instead of inventing a problem. Ask me who the message is going to and how formal our usual communication is before you start, if that would change your answer. Here is the message: [paste message]

You are an editor helping a manager turn rough notes into a short paragraph for a formal performance review. I will give you bullet points of feedback for one employee. Write one paragraph, no more than 120 words, that sounds like my own voice: direct, specific, and free of corporate filler phrases. Keep every concrete detail from my bullets (dates, numbers, project names); do not add praise or criticism I did not give you. If my bullets are too thin to write a fair paragraph, tell me what detail you need instead of guessing. Here are my bullet points: [paste bullets]

You are helping me decide whether to pay for a writing checker tool, based only on my real weekly usage, not marketing claims. Ask me: how many messages or documents I write per week, their typical length, whether I need full-sentence rewrites or just grammar catches, and whether I write in more than one language. Based on my answers, tell me plainly whether a free plan would cover my week or where it would run out (name the specific cap it would hit), and name which single paid tier would fix that gap and its monthly cost. Do not recommend a plan before asking these questions.

Act as a blunt hiring manager who has read ten thousand resumes, not a career coach. I will paste my full resume and the job description I want. Rewrite the whole resume for that role, section by section, in this order: summary, experience, skills, education. Rules: every experience line leads with impact, not duty. Use bracketed placeholders like [8 percent] for any number I did not give you, and list at the end every placeholder I need to replace with a real figure. Keep it to one page of text. Plain formatting only, no tables or columns, so screening software can parse it. After the rewrite, tell me the three weakest claims that need evidence before I send this anywhere. My resume: [paste resume]. The role: [paste job description].