If you want help with everyday writing at no cost, Grammarly and QuillBot both have free plans. The cheapest confirmed paid plan is QuillBot Premium at $4.17 a month, billed annually. Grammarly Pro costs $12 per member a month billed annually, or $30 billed monthly. Jasper Pro, aimed at marketing workflows, costs $59 a month billed annually, or $69 billed monthly. Writesonic starts at $79 a month billed annually, but its plans now center on tracking how brands appear in AI search answers rather than on general writing help.
This is a documentary comparison based on the providers’ official pages. We have not tested, bought or installed any of these tools, so nothing here rates the quality of their writing, suggestions or detection. Feature descriptions below are the providers’ own claims.
What these tools do, and what they do not
Grammarly and QuillBot mainly correct and rephrase text you have already written. Jasper and Writesonic mainly produce marketing content. None of them checks whether your claims are true, and none replaces a human review before you publish. If you need one assistant for many kinds of work, read our guide to choosing a general AI assistant for real tasks or AI assistant subscriptions compared.
Paid plans side by side
Prices and plan details were checked on the providers’ official pages on 5 November 2026. Figures are in USD as displayed. Prices vary by country, currency, taxes and promotions, so confirm the final amount at checkout. QuillBot’s prices were read on its premium page in a browser; other QuillBot figures that circulate online are not used here.
| Item | Grammarly Pro | QuillBot Premium | Jasper Pro | Writesonic Starter |
|---|---|---|---|---|
| Monthly billing | $30 per member/month | Not confirmed | $69/month | Not confirmed |
| Annual billing | $12 per member/month | $4.17/month | $59/month | $79/month |
| One year on annual billing | $144 per member (12 × 12, our arithmetic) | $50.04 (4.17 × 12, our arithmetic) | $708 per seat (12 × 59, our arithmetic) | $948 (12 × 79, our arithmetic) |
| Usage limit | 2,000 AI prompts per member/month | Plagiarism checks up to 25,000 words/month; summarize 6,000 words | Word or credit allowance not stated | 15 AI articles/month |
| Seats | 1 to 149 | 1 (Team offer exists, price not shown) | 1 (contact sales for more) | 1 user, 1 project |
| Free trial | Yes, length not confirmed | Not confirmed | 7 days | “Start free”, length not confirmed |
| Refunds | Non-refundable | Not confirmed | No refunds on cancellation | Full refund within 7 days of first purchase |
Monthly billing costs much more over a year. Paying Grammarly Pro monthly for 12 months would come to $360 per member, against $144 on annual billing (our arithmetic). Jasper says annual billing saves “~20%”. Its own displayed prices imply less: $69 × 12 is $828 a year on monthly billing, against $708 on annual billing, a saving of $120, or about 14.5% (our arithmetic).
Free plans and their limits
Grammarly Free corrects spelling and grammar and includes 100 AI prompts a month. It does not include tone adjustment, full-sentence rewrites, AI-text detection, the plagiarism check, style guides or brand tones. You can check the current offer on Grammarly.
QuillBot Free costs $0, with usage limits that QuillBot says may vary by surface. It paraphrases up to 125 words in Standard and Fluency modes, summarizes up to 1,200 words, runs its humanizer on up to 125 words with limited usage and gives 10 MB of Flow storage.
Jasper shows no free plan, only a 7-day trial of Pro. Writesonic shows no permanent free plan; its pricing page says “Start free. No credit card needed.” without saying for how long.
Plagiarism and AI-detection features
Grammarly Pro and Enterprise add a check for accidental plagiarism and detection of AI-generated text. QuillBot says all Premium plans include a plagiarism checker, an AI detector and an AI humanizer. You can see what Premium currently includes on QuillBot. Jasper’s comparison table shows a plagiarism checker on Pro, described as a Copyscape add-on; whether it is included in the price was not confirmed. The Writesonic plan lists we read mention no plagiarism or AI-detection tool. Whatever you use, do not treat a detector’s score as the only evidence when judging someone’s work.
Brand voice, style guides and seats
Grammarly Pro includes one style guide, one brand tone, two user groups and a team analytics dashboard, for 1 to 149 seats. Enterprise, priced through sales, adds unlimited prompts, style guides and brand tones, plus SAML single sign-on and data loss prevention.
Jasper Pro includes two Brand Voices, three Audiences and five Knowledge assets for one seat, with image tools and more than 30 languages. Jasper Business is custom-priced and adds unlimited Brand Voices, style guides, API access and SSO, with a minimum 12-month commitment. Jasper accepts major credit and debit cards only. You can check the current offer on Jasper.
QuillBot Premium lists 9 paraphrase modes plus unlimited custom modes and 23 paraphrase languages, but no brand voice feature in the details we read.
Writesonic: now an AI search visibility tool
Writesonic now presents itself as a platform for tracking how often a brand appears in answers from AI search tools such as ChatGPT, Gemini and Google AI Overviews, with AI-written articles included as a monthly quota. Its self-serve plans, at annual-billing prices:
- Starter: $79 a month, or $948 a year (our arithmetic), for 1 user, 50 tracked prompts and 15 AI articles a month.
- Basic: $199 a month, or $2,388 a year (our arithmetic), for 2 users, 100 tracked prompts and 25 AI articles a month.
- Growth: $399 a month, or $4,788 a year (our arithmetic), for 3 users, 200 tracked prompts, 50 AI articles a month and sentiment analysis.
Extra users cost $50 per user per month, up to five users in total. Monthly-billing prices were not shown. Self-serve plans carry a full refund of the initial fee within 7 days of first purchase. If AI search visibility is your goal, check the current offer on Writesonic.
Trials, refunds and renewals
Grammarly’s Pro trial shows “$0 payment today” and sends an email reminder 2 days before it ends. Its terms say all payments are non-refundable. Plans renew for the same period until you cancel; the account then returns to Free at the end of the billing cycle.
Jasper’s terms say no notice is sent when the trial ends, so cancel before midnight Pacific time on the last trial day if you do not want to pay. Monthly Pro renews until cancelled and can be paused for 30 days; annual billing is a 12-month commitment paid up front.
Writesonic plans renew for a term equal to the first one, and cancellation takes effect at the next billing cycle. QuillBot’s refund and renewal terms were not confirmed, so read them at checkout.
Will your text be used to train AI models?
- Grammarly: its Product Improvement and Training control is on by default for Free and single-user Pro accounts, and you can turn it off in your settings. For multi-user Pro bought on the website it also starts on, and only admins can change it. For accounts bought through sales, including Enterprise, it is off by default. Grammarly says it does not let third parties train models on user content.
- QuillBot: not confirmed; we could not read its terms.
- Jasper: its terms let it use your inputs and outputs to develop and enhance its AI models. EU and UK users may object, as its terms describe.
- Writesonic: its terms say it does not use customer data to train general-purpose or large language models unless you opt into a separate program, and that trial inputs and outputs are not used either.
Whatever the policy, do not paste client data, contracts or personal information into any of these tools until you have checked your account settings. Our guide to classifying data before using AI tools shows how to sort what can go in.
How to decide
Start with Grammarly Free or QuillBot Free if you want no cost. Choose QuillBot Premium if a low confirmed annual price with a plagiarism checker and AI detector matters most, knowing its refund policy is not confirmed. Choose Grammarly Pro if a team of up to 149 people needs a shared style guide and AI-text detection, and you accept non-refundable payments. Choose Jasper Pro for marketing content with brand voices, and plan around its no-notice trial end. Consider Writesonic only if tracking your brand in AI search answers is the main goal. For a team rollout, see our guide to deploying a team AI assistant with human review.
- Decide what you need: corrections, rephrasing, marketing drafts or AI search tracking.
- Count seats: Grammarly Pro goes up to 149; Jasper Pro and Writesonic Starter are one user.
- Check the limit: prompts at Grammarly, words at QuillBot, articles at Writesonic.
- Compare annual and monthly billing over 12 months.
- Note the refund rule: 7 days at Writesonic, none at Grammarly or Jasper, not confirmed at QuillBot.
- Set a reminder before any trial ends.
- Turn off training on your text where you can.
- Confirm the final price, taxes and currency at checkout.
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