Grammarly's Free Plan Is 100 Prompts a Month. The Real Cap Is Lower.
The 100-prompt cap is the one everyone quotes. The document limit underneath it is the one that catches long-form writers.
Grammarly Free gives 100 AI prompts a month, grammar and spelling correction, and basic tone detection, permanently and with no trial clock. Full-sentence rewrites, tone adjustment and plagiarism detection all sit behind Pro at $12 a month billed annually. The AI prompt cap is the limit most reviews quote, and it is not the one that catches long-form writers.1
Underneath the prompt cap there is a second limit that applies to every plan, including Pro, and almost nobody writes about it: in any 30-day period you can check up to 300 documents or 150,000 words, and in any 24-hour period up to 100 documents or 50,000 words.
Chintan Dhokai has used Grammarly daily since 2021 and hit both caps. The prompt limit arrives first for people who draft with AI. The document limit arrives first for people who edit long manuscripts.
What the free plan actually includes
| Feature | Free | Pro ($12/mo annual) |
|---|---|---|
| AI prompts per month | 100 | 2,000 per member |
| Grammar, spelling, punctuation | Yes | Yes |
| Tone detection | Yes, detection only | Detection and adjustment |
| Full-sentence rewrites | No | Yes |
| Plagiarism checker | No | Yes |
| AI-text detector | Limited | Yes |
| Personalised suggestions | Limited | Unlimited |
The distinction on tone matters and it is easy to miss. Free tells you that a paragraph reads as defensive. Pro offers to rewrite it so that it does not. Detection without adjustment is a diagnostic, not a fix.
The document limit nobody mentions
Grammarly's own support documentation states that in any 30-day period an account can check up to 300 documents or 150,000 words, and in any 24-hour period up to 100 documents or 50,000 words. That applies to Free and Pro alike.
150,000 words a month is a generous ceiling for a student. It is roughly one and a half novels, so a book editor will meet it, and a content team running a large blog will meet it every month. The daily limit bites sooner on a heavy editing day, because every file you open counts as a document.
What counts as a document is the part that surprises people. Open the same file in the browser and in the desktop app and check it twice, and that is two. Paste a long passage into the web editor rather than opening the file, and it is another.
100 prompts is about three a day
Spread across a 30-day month, 100 prompts is three and a third per day. That is enough to test the AI features. It is not enough to draft with them.
| How you use it | Prompts per day | Days until the cap |
|---|---|---|
| Occasional AI use, correcting a phrase | 1 to 2 | 50 to 100, so within a month |
| Drafting two paragraphs a day | 5 | 20 |
| Rewriting a full email each morning | 10 | 10 |
| Using the rewrite and reply features all day | 30 | 3 to 4 |
There is no way to buy more prompts. When the allowance is gone the generative features stop working until the monthly reset, and unused prompts do not roll over into the next month.
When the free plan is genuinely enough
For someone writing short, English-language, low-stakes text, the free plan is a complete product. Emails, Slack messages, a paragraph of copy, a CV. Grammar, spelling and punctuation correction is the part of Grammarly that works best, and it is not metered.
The free plan stops being enough at the point where you need the rewrite rather than the correction. If you regularly find yourself reading a suggestion, agreeing with it, and retyping the sentence yourself, you are paying the upgrade price in time instead.
What to do instead of paying $12
Two free products cover what the Grammarly prompt cap restricts, and neither asks for a card.
- Draft in a free AI assistant and paste the result into Grammarly Free for correction. The writing happens elsewhere, and the 100 prompts stay unused because you never pressed the generate button.
- Use QuillBot Free for paraphrasing, with the caveat that its cap is 125 words per pass, which is one paragraph. For longer rewrites it is worse value than Grammarly Pro.
The order matters. Correcting text is unmetered on both free plans. Generating text is metered on both. Do the generating outside the tool that meters it.
Frequently asked questions
Does Grammarly Free require a card?
The free plan is permanent and does not expire. A payment method is only needed if you choose to upgrade to Pro.
What happens when the 100 prompts run out?
Generative features stop working until the allowance resets. There is no overage charge, and there is no way to buy additional prompts.
Do unused prompts carry over?
No. The allowance resets on the monthly anniversary of the date generative AI was first activated on your account, not on your billing date.
Is the document limit different on Pro?
No. The 300-document and 150,000-word monthly ceiling, and the 100-document and 50,000-word daily ceiling, apply to Free and paid accounts alike.
Is grammarly free plan enough for students?
Usually yes. A student will rarely approach 150,000 words a month, and the correctness checking that matters for coursework is not metered.
Free-tier limits verified against Grammarly's plans page and support documentation on 19 October 2026. Limits change without notice.
Sources
- Grammarly plans and pricing: www.grammarly.com/plans. Used for: Free and paid tier comparison.
All sources are the vendor's own plan or documentation pages, checked on 20 October 2026. Plan terms change without notice, so confirm current limits before you rely on them.
