Most people who install Grammarly never pay a cent for it. They see the green underline, accept a couple of comma fixes, and move on. That’s a perfectly reasonable way to use it. The free tier isn’t a time-limited trial that nags you into a subscription after two weeks — it’s a permanent product, and Grammarly keeps it that way on purpose.
It also has a hard ceiling. Knowing exactly where that ceiling sits is the difference between paying for features you’d never touch and grinding through bad suggestions you could fix for free elsewhere.
What the Free Plan Actually Catches
The core checks are the same ones Grammarly built its reputation on, and they run on every sentence you type.
- Spelling and typos, including the ones your word processor misses because they’re real words in the wrong place (“form” instead of “from”).
- Grammar and punctuation, with the green underline for correct-but-worth-a-look items and red for genuine mistakes.
- Conciseness suggestions that flag wordy phrases. Free users do get these, which surprises a lot of people.
- Tone detection, which labels a message as confident, formal, worried, or friendly before you hit send.
- Basic clarity alerts for tangled sentences and passive constructions.
The 100 AI prompts a month
Grammarly now leans heavily on generative features, and the free plan includes a monthly allowance of AI prompts — currently 100. That sounds generous until you realise one “improve this paragraph” request can burn a single prompt, and rewriting a five-paragraph email can eat five. Heavy users blow through the cap in a week. Light users never notice it exists.
What you get inside that allowance is mostly rewriting and short generation: tightening a sentence, rephrasing a blunt reply, drafting a quick summary. It’s genuinely handy, just not unlimited.
Where Grammarly Free Stops
The paywall sits in a fairly predictable place. Free catches errors; Pro tries to improve the writing itself.
Full-sentence rewrites
Free will suggest swapping a word or trimming a clause. It won’t rebuild a clumsy sentence from scratch and hand you three cleaner versions. That full-sentence rewrite engine is the feature most people are actually paying for, and it only unlocks on Pro — roughly $12 a month billed annually, or $30 if you pay month to month.
Plagiarism detection
Grammarly’s plagiarism checker compares your text against billions of web pages and academic papers. It’s Pro-only. If you’re a student or someone publishing regularly, this is often the single feature that tips the decision, because running your draft through a separate plagiarism tool costs about the same as the upgrade.
Adjusting tone, not just detecting it
Free tells you a message reads as “aggressive.” Pro can rewrite it into something diplomatic with one click. That gap between noticing a problem and fixing it is the pattern across the whole free plan.
Everywhere Grammarly Free Follows You
The browser extension is the workhorse. It runs inside Gmail, LinkedIn, Slack, Notion, Google Docs and a claimed 500,000-plus other sites, which is why so many people forget it’s installed at all. There’s also a desktop app for Windows and macOS that works in any text field, add-ins for Microsoft Word and Google Docs, and a mobile keyboard for iOS and Android that spell-checks your texts and DMs.
The mobile keyboard is the piece people underrate. If you write long messages on your phone — client replies, applications, anything with consequences — it’s the highest-value free feature in the whole product. It’s also the kind of thing that shows up on lists of genuinely useful AI tools that earn their place on your phone rather than collecting dust.
Getting More Out of the Free Tier
A few habits stretch the free plan considerably.
- Write in Grammarly’s editor, not in the browser box. The standalone editor surfaces every suggestion at once and lets you accept them in bulk, which takes about a quarter of the time.
- Check the alert before you accept it. Free suggestions are good but not infallible, especially with names, technical terms, and idioms. Blindly accepting everything produces stiff, over-punctuated prose.
- Set your audience and formality correctly. Grammarly tailors its suggestions to the context you pick. Wrong setting, wrong advice.
- Save long AI prompt requests for one big ask. Instead of feeding a document in paragraph by paragraph, select the whole section and request one rewrite. Same output, one prompt spent.
- Upload documents to the web editor to get a full pass without pasting text into a browser field in chunks.
Free Grammarly vs. Other Free Writing Tools
Grammarly isn’t the only free option, and for some jobs it isn’t the best one. Wordtune’s free tier takes a different approach — fewer grammar rules, more emphasis on rephrasing sentences you already know are grammatically fine but don’t quite land. If your problem is not errors but flat, repetitive phrasing, that’s worth a look; the Wordtune review breaks down what the free version covers and what it holds back.
There’s also a wider field of AI writing and productivity apps with no paid tier at all. Some are excellent. Plenty waste an afternoon on setup and produce nothing usable. A roundup of free AI tools worth trying in 2025 is a faster way to sort the two than installing everything yourself.
One thing no free tool does reliably is tell you whether text was machine-written. Grammarly’s own AI detector, and every competitor’s, produces false positives on formal human writing and misses lightly edited AI output. Given how quickly people have learned to strip machine watermarks and pattern markers from generated text, treat any detector’s verdict as a hint rather than evidence.
What Free Costs You Beyond Money
Grammarly’s privacy terms differ between tiers. Content from free accounts can be used to improve the company’s models; paying users get the guarantee that their text won’t be used for training. For most personal writing that’s a non-issue. If you’re pasting in legal drafts, unpublished research, or anything under NDA, the free plan is the wrong place for it — and that applies to every free AI writing tool, not just this one.
Advertising is a non-factor. Grammarly doesn’t run ads against your text, and it doesn’t sell your data to third parties. The trade is model training, not banner space.
Who Should Stay on the Free Plan
If you write emails, cover letters, social posts, and the occasional report, the free tier covers the vast majority of mistakes you actually make. The extra features on Pro — plagiarism checking, full rewrites, tone adjustment — address problems most casual writers either don’t have or can solve by rereading their draft once out loud.
Upgrade when one specific thing keeps blocking you. Students and researchers get real value from plagiarism detection. People who write long-form content professionally usually save enough editing time in a month to cover the $12. Anyone constantly hitting the AI prompt limit and noticing it has effectively outgrown the free plan on their own.
For everyone else, the green underline does most of the work for nothing. Keep it installed, ignore the upgrade banners, and put the money toward something that solves an actual problem.