Best AI tools to correct grammar
Top picks at a glance:
- LanguageTool — An AI-based writing assistant that checks text for grammar mistakes and helps you find the right tone.
- GPTZero — AI detection software that identifies text generated by large language models.
- Walter Writes AI — An AI humanizer and detection platform that rewrites AI-generated text to sound natural and identifies AI-written content.
- iAsk AI — An AI search engine and homework helper that provides factual, cited answers using transformer neural networks.
- Originality.ai — AI detection, plagiarism checking, fact checking, readability, and grammar checking tools for content integrity.
| Tool | What it does | Pricing | Free tier | Refunds |
|---|---|---|---|---|
| LanguageTool | An AI-based writing assistant that checks text for grammar mistakes and helps you find the right tone. | Free tier; paid from $5.83/mo | Yes | 14 days |
| GPTZero | AI detection software that identifies text generated by large language models. | Free tier; paid from $12.99/mo | Yes | None stated |
| Walter Writes AI | An AI humanizer and detection platform that rewrites AI-generated text to sound natural and identifies AI-written content. | Free tier; paid from $8/mo | Yes | 3 days |
| iAsk AI | An AI search engine and homework helper that provides factual, cited answers using transformer neural networks. | Free tier; paid from $9.95/mo | Yes | — |
| Originality.ai | AI detection, plagiarism checking, fact checking, readability, and grammar checking tools for content integrity. | Free tier; paid from $12.95/mo * | Yes | — |
— means the vendor does not state it on the pages we read.
* pricing not verified against the vendor's pricing page.
How do I choose an AI tool to correct grammar?
When selecting an AI tool to improve your writing, first identify which platforms you need, as options vary from web-only browsers to those supporting iOS, Android, and desktop environments. Consider whether you require an API for your workflow. Carefully compare the pricing tiers, which range from $5.83 to $12.99 per month, and pay close attention to subscription terms. Some platforms offer a 14-day or 3-day refund window, while others state no refunds are available. Finally, check the stated limits for each tool; verify if your intended usage complies with commercial restrictions, HIPAA/FISMA regulations, or account sharing policies. By matching these specific platform capabilities and business terms to your project requirements, you can effectively narrow down the best solution for your grammar checking needs.
LanguageTool
Visit LanguageToollanguagetool.orgCancellation & refund terms for LanguageTool

An AI-based writing assistant that checks text for grammar mistakes and helps you find the right tone.
LanguageTool finds every mistake and underlines it in red. Spell every name, phrase, and word the write… eh, the right way!
Pricing, in their words: “Choose payment interval Your current plan 2 years $119.80 /2 years $4.99 per month Annual BESTSELLER $69.90 /year $5.83 per month Quarterly $49.90 /quarter $16.63 per month Monthly $24.90” (pricing)
Subscription terms they state: cancel in-app · auto-renews · 14-day refund window (source)
Limits the vendor states:
- commercial use restricted
GPTZero
Visit GPTZerogptzero.meCancellation & refund terms for GPTZero

AI detection software that identifies text generated by large language models.
Correct grammar and spelling errors
Pricing, in their words: “$12.99/ month, billed annually” (pricing)
Subscription terms they state: cancel in-app · auto-renews · states no refunds (source)
Limits the vendor states:
- not for commercial use
- not 100% accurate
Walter Writes AI
Visit Walter Writes AIwalterwrites.ai
An AI humanizer and detection platform that rewrites AI-generated text to sound natural and identifies AI-written content.
Grammar Checker Fix grammar without sounding like AI.
Pricing, in their words: “Starter 30,000 words/month $ 8 Per month , Billed $96 Annually” (pricing)
Subscription terms they state: cancel in-app · auto-renews · 3-day refund window (source)
Limits the vendor states:
- guarantee avoidance of ai detection
- use for hipaa/fisma-regulated data
iAsk AI
Visit iAsk AIiask.ai
An AI search engine and homework helper that provides factual, cited answers using transformer neural networks.
iAsk can help to fix your grammar with just one click, ensuring polished written content effortlessly.
— iask.ai
Pricing, in their words: “$9.95 per month” (pricing)
Limits the vendor states:
- Account sharing
Originality.ai
Visit Originality.aioriginality.ai
AI detection, plagiarism checking, fact checking, readability, and grammar checking tools for content integrity.
Our best in class AI enabled Grammar & Spell Checker enhances your text by using the top-rated tool for checking Grammar & Spelling.
Pricing: Free tier; paid from $12.95/mo (pricing)
Subscription terms they state: cancel in-app · auto-renews (source)
No usage limits stated on the pages we read.
FAQ
Is there a free tool to correct grammar?
Yes — LanguageTool, GPTZero, Walter Writes AI, iAsk AI, Originality.ai offer a free tier.
What is the cheapest paid option to correct grammar?
LanguageTool starts at $5.83/month.
Which of these have an API?
LanguageTool, GPTZero, Walter Writes AI, iAsk AI, Originality.ai document a developer API.
How do I cancel these subscriptions?
LanguageTool: cancel in-app; GPTZero: cancel in-app; Walter Writes AI: cancel in-app; Originality.ai: cancel in-app. iAsk AI does not state a cancellation route on the pages we read.
Can I get a refund?
LanguageTool states a 14-day refund window; GPTZero states it does not offer refunds; Walter Writes AI states a 3-day refund window. The others (iAsk AI, Originality.ai) do not state a refund policy on the pages we read.
Do these subscriptions auto-renew?
LanguageTool, GPTZero, Walter Writes AI, Originality.ai state that paid plans renew automatically. Check the billing page before subscribing; the rest do not state it either way.
Sources
Every fact above was read from the vendors' own pages: