2026 Interactive Cost & ROI Calculator
| Plan | Effective / Mo | 1-Year Total | 3-Year Total | Plagiarism & AI Limit | Action |
|---|---|---|---|---|---|
Grammarly Free Free Forever | $0/mo | $0/yr | $0 | 100 prompts/mo Plagiarism: No | Try Grammarly Free |
Grammarly Pro Best for Teams, Business & Academic | $12/mo | $144/yr | $432 | 2,000 prompts/mo Plagiarism: Yes (Pro-Archive & web scan) | Try Grammarly Pro (Save 60% Annual) |
ProWritingAid Premium Best for Fiction & Long Manuscripts | $10/mo | $120/yr | $360or $399 once (Lifetime) | 25+ in-depth manuscript & pacing reports Plagiarism: Paid add-on credits | Try ProWritingAid |
LanguageTool Premium Best for Multilingual & Budget | $5/mo | $60/yr | $180 | Unlimited style & paraphrasing in 30+ languages Plagiarism: No | Compare LanguageTool |
Cost takeaway: Paying monthly for Grammarly Pro costs $360/year ($30/mo), whereas switching to annual billing drops the price to $144/year ($12/mo), saving you $216 per year. If you plan to keep an editor for 3+ years, compare Grammarly Pro ($432 over 3 years) against ProWritingAid Annual ($360 over 3 years).
A screen-share comparison of the free and paid Grammarly tiers, covering the self-editing features and writing reports the upgrade unlocks.
Grammarly Free covers grammar, spelling, punctuation, tone detection and 100 generative-AI prompts a month, and it is genuinely useful on its own. Grammarly Pro, the plan formerly called Premium, adds full-sentence rewrites, tone rewriting, plagiarism detection and 2,000 AI prompts a month. Which one is right depends on how much you write and whether you draft with AI. Here is the full comparison.
Want to test the free plan first? Try Grammarly free and see how far it gets you, or check our Grammarly discount guide before upgrading. Affiliate link. We may earn a commission at no extra cost to you.
A quick note on naming: Grammarly renamed its paid “Premium” plan to “Grammarly Pro” in late 2024. We still say “Premium” in places because that is the term most writers search for, but the plan you will see at checkout is Grammarly Pro. The standalone Business tier is gone; Pro now covers both individuals and teams, with a custom-priced Enterprise plan above it. For the full hands-on verdict, read our Grammarly review.
| Feature | Free | Pro (formerly Premium) |
|---|---|---|
| Grammar, spelling, punctuation | Yes | Yes |
| Tone detection | Yes | Yes |
| Generative-AI prompts per month | 100 | 2,000 |
| Full-sentence rewrites | No | Yes |
| Tone adjustment and rewriting | No | Yes |
| Fluency suggestions | No | Yes |
| Vocabulary and word-choice suggestions | Limited | Full |
| Plagiarism and AI-text detection | No | Yes |
| Works in browser, Docs, email, mobile | Yes | Yes |
| Typical price | Free | Around $12/month billed annually (geo-tested) |
The allowances above are published on grammarly.com/plans. Prices are tested by region and change often, so confirm the current figure at checkout, and check our Grammarly coupon guide before you buy.
Grammarly Free is more than a spell checker. It catches subject-verb agreement errors, misused articles, misplaced modifiers and the typos that slip past tired eyes, and it flags wordiness so you write more directly (“in order to” becomes “to”). It also includes basic tone detection and a monthly allowance of 100 generative-AI prompts, so you can sample the AI rewrite features before deciding whether to pay.
For students writing everyday assignments, casual bloggers, and anyone who wants a reliable safety net on emails and social posts, the free plan is often all you need. It is a clear step up from a built-in word-processor checker, at no cost.
Pro takes the same corrections and goes deeper, plus it unlocks the generative-AI features most writers upgrade for.
Grammarly Free costs $0 forever. Grammarly Pro (formerly Grammarly Premium) costs $12 per member per month when billed annually ($144/year), $20 per month when billed quarterly ($60 every 3 months), or $30 per month when billed month-to-month.
| Billing Tier | Monthly Rate | Upfront Bill | Annualized Cost | Annual Savings vs Monthly |
|---|---|---|---|---|
| Grammarly Free | $0/mo | $0 | $0/yr | Baseline |
| Grammarly Pro (Annual) | $12/mo | $144 once a year | $144/yr | Save $216/yr (60% off) |
| Grammarly Pro (Quarterly) | $20/mo | $60 every 3 months | $240/yr | Save $120/yr (33% off) |
| Grammarly Pro (Monthly) | $30/mo | $30 every month | $360/yr | $0 |
| Grammarly Enterprise | Custom | Custom annual contract | Custom | Unlimited AI prompts + SAML SSO |
The gap between monthly and annual billing is the biggest pricing trap in Grammarly’s checkout flow:
The cleanest way to decide is to start on Free, use it for a couple of weeks, and notice what you keep wishing it could do. If the answer is “rewrite this whole sentence,” “match this tone,” “check this for plagiarism,” or “give me more AI prompts,” those are all Pro features, and you have your answer.
Both plans make you a more confident writer. Free is a dependable safety net that catches the errors that undermine credibility. Pro is the upgrade for people whose writing carries real weight, adding rewrites, tone control, plagiarism detection and a 20-times-larger AI allowance. Pick the one that matches how much you write and how much you lean on AI, and read our full Grammarly review if you want the complete hands-on picture before deciding.
About this guide: Written by Bryan Collins, writer and founder of Become a Writer Today. Our recommendations are based on hands-on testing and independent research. Become a Writer Today does not accept payment for rankings or recommendations.
Grammarly Free provides real-time checks for grammar, spelling, punctuation and basic sentence structure, plus tone detection and 100 generative-AI prompts per month. It works across browsers, Google Docs, Gmail and most apps. It does not include full-sentence rewrites, tone rewriting, or plagiarism detection.
Grammarly Pro, renamed from Premium in late 2024, adds full-sentence rewrites, tone adjustment, fluency suggestions, unlimited personalised writing suggestions, a plagiarism and AI-text detector, and a far larger allowance of 2,000 generative-AI prompts per month, up from 100 on Free.
Grammarly Free includes 100 generative-AI prompts per month. Grammarly Pro includes 2,000 prompts per member per month, and the Enterprise plan is unlimited. If you regularly use Grammarly to draft or rewrite rather than just fix errors, that gap is the main reason to upgrade.
Grammarly Pro costs roughly $12 per month when billed annually, with higher effective rates on shorter billing terms. Pricing is geo-tested and changes often, so confirm the current figure on the checkout page. Pro now covers both individuals and teams; larger organisations use the custom-priced Enterprise plan.
For casual emails, short assignments and social posts where basic accuracy is the goal, Grammarly Free is usually enough. Students submitting academic papers benefit from Pro's plagiarism detection and advanced clarity suggestions, and anyone who drafts with AI will hit the 100-prompt free cap quickly.
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