10 Best AI Grammar Check Tools in 2024 (Free & Paid)
What do AI grammar check tools do?
AI grammar check tools use artificial intelligence and natural language processing to analyze and correct written text. They identify and fix spelling errors, grammar and syntax issues, and punctuation mistakes, and provide style and vocabulary suggestions.
Whether you have an academic text to hand in to your professor, a work report that needs to be flawless when it reaches your boss’s desk, or are working on your first novel, these tools can improve the quality of any written content. But with countless paid and free AI grammar checkers available online, how do you choose the right one?
We have compiled a list of some of the most popular grammar tools out there and compared their capabilities as objectively as possible (see the final section of this article where we explain our methodology). Before you trust a grammar checker with your writing, read on and find out which one offers what you need!
Wordvice AI review—best all-around writing assistant
The Wordvice AI Writing Assistant finds and corrects grammar, punctuation, and word choice errors in academic papers, assignments, business emails, and other English-language documents. It also suggests vocabulary, tone, and style improvements and provides easy-to-understand explanations and feedback that helps you improve your writing over time. The advantage of the Wordvice free AI Proofreading Tool is that it consists of an entire suite of AI text editing tools (the AI Paraphraser, AI Text Summarizer, AI Translator, and free AI Plagiarism Checker) that can be applied separately—this means that you are entirely in control of how much you are willing to change the original version of your text. The Wordvice team of specialized editors also offers professional proofreading services in case you want an extra set of eyes to check your text before it goes out to the world.
Grammar check quality: high
The Wordvice AI Proofreader detected all of the mistakes in our sample text and provided helpful explanations for the necessary changes. It also suggested different wording where the clarity of the text could be improved or where human input was required to decide between slightly different interpretations.
Usability and pricing
Wordvice AI's grammar checker has a clean and straightforward interface and is very easy to use. It only requires a free sign up, so you can just copy-paste some example sentences into the text box and try it out (and while you are at it, make sure you try the paraphrasing, summarizing, and translating functions out as well). What is really cool about this tool is that it offers different levels of editing depth (light - standard - intensive - concise) and adapts to different types of texts (e.g., academic - business - creative). Some of those only come with the paid Premium version, which is, however, quite affordable at $9.95/month annually (and just a little more pricey at $15.95/month every 6 months or $19.95/month on the monthly plan).
ProWritingAid review—a grammar checker for creative writing
ProWritingAid is not the most highly-recommend AI tool to use if you want to impress someone with your writing. It spotted several of the errors in the text we fed it and introduced some new mistakes while making corrections. It also flagged random verbs as “business jargon” that should be avoided (note that our example text is academic) and let us know repeatedly that a sentence was “too complex,” without specifying how to proceed, when the sentence did in fact contain grammar problems.
Grammar check quality: low
The tool identified only the most simple mistakes (i.e., wrong verb forms), suggested changes that contained some new errors, and didn’t provide clear explanations or instructions.
Usability and pricing
The tool comes with a browser extension and allows you to accept corrections with a click, but we found the interface crowded and distracting. We also didn’t know what to make of the somewhat mysterious “scores” it displayed, and don’t like the fact that you need to sign up for an account before you can even try it out.
The free version lets you access all of the grammar tools but restricts your texts to 500 words, while the Premium membership (€10/month annually or €30/month monthly) works on unlimited words and offers an additional list of features ranging from practical (check in-line citations) to somewhat mysterious (e.g., compare your writing to fiction authors across different genres).
WhiteSmoke review—comprehensive writing aid with tutorials
WhiteSmoke seems to be a trusted tool used by major universities and corporations, but we think there are better ones out there in 2024. It can detect a number of grammar issues as well as monotonous sentence length and tense switching, and comes with a translator that works on 55 different languages. It did not perform flawlessly on our text, however, and does not seem to offer any kind of trial version or period, and the demo is too basic to get a real idea of what WhiteSmoke can do.
Grammar check quality: medium
The web-based demo version did correct most mistakes in our text but also found additional ones where none existed. To receive any explanations, one needs to sign up for a paid version.
Usability and pricing
The WhiteSmoke web version is available on all popular web browsers. It lets you correct mistakes with a single click and offers video tutorials and over 100 templates for various writing projects. The only issue is, as already mentioned, that you cannot try it out before signing up for a paid version. You can sign up for either the web version, at $59.95 annually ($5.00 per month) or the Essential ($79.95 annually; $6.66 per month) or Premium ($11.50 per month, billed as one yearly payment of $137.95) desktop versions.
Grammarly review—the most popular free grammar checking tool
Everyone has heard of Grammarly (around 20 million people are using it currently), and there is a reason it is so popular—the tool performed well overall on our sample, has a clean look and makes suggestions so that you can go through them to make sure the corrected text conveys your intended meaning. Moreover, it recognizes many technical terms, including abbreviations and acronyms, and doesn’t flag them as mistakes.
However, there is a significant difference between the free and the paid versions of Grammarly: the free version doesn’t just offer fewer functions, it identifies and fixes fewer errors (and labels the one that it could fix but only if you pay for a Premium account).
Grammar check quality: high
Grammarly noticed all errors and offered to fix most of them (with clear suggestions) but referred us to their paid Premium version to see explanations for some mistakes. It also lets you choose the formality level and audience of your text (although some of these features are also only available in the Premium version).
Usability and pricing
Grammarly is compatible with all popular internet browsers and Microsoft Office, and it has an overall clean, easy-to-understand interface. Fixing errors takes a bit longer than necessary, however, because it requires two clicks for each correction. You need to sign up to try it out and pay to get all your mistakes fixed: Grammarly Premium comes at $29.95/month, $19.98/month, or $11.66/month for monthly, quarterly, or annual subscriptions.
Quillbot review—the all-in-one AI writing and revision tool
Quillbot can be tried out without signing up and offers a variety of other tools (although most are only available in the paid version). It performed very well on our text and corrected all of the errors we introduced—although it didn’t offer any explanations or suggestions other than the necessary corrections. But since its output was accurate overall, the “Fix all errors” button came in very handy.
Grammar check quality: high
Quillbot knows what it’s doing and fixed all the grammar errors we introduced into our text. And while it didn’t explain much and didn’t offer suggestions to improve the writing further in terms of clarity or flow, the edited text was fine overall.
Usability and pricing
Quillbot has a neat, user-friendly interface and doesn’t distract the user with unnecessary information. It offers a browser extension,and the “fix all errors” option can save you a lot of time. You don’t need to sign up just to try it out, but if you want to get texts of more than 125 words checked at once and receive suggestions on your writing, you need to upgrade to Premium, which costs $8.33 (annually), $13.33 (semi-annually) or $19.95 (monthly) per month.
Hemingway Editor review—the original grammar and spelling checker for authors
The Hemingway App gets its namesake from the American writer Ernest Hemingway, who is famous for his concise and “muscular” writing style. As its name suggests, this tool promises to not only check your grammar but also make sure that you don’t write long and unnecessarily complicated sentences. It comments on your use of adverbs and passive voice, suggests alternatives, and flags complicated sentences so that you can divide or rearrange them.
Grammar check quality: low
We were very impressed with the tool’s ability to suggest clearer wording, and the edited text does flow extremely well. However, the Hemingway Editor didn’t bother with some of the simple mistakes our text contained and only fixed those that happened to occur in long sentences it wanted to rewrite anyway. Also note that “AI corrections” are only offered in the paid version.
Usability and pricing
The browser-based software is free but you need to sign up with your email address. It lists useful text-related statistics such as use of passive voice and hard-to-read sentences while keeping the interface clean overall. It does, however, flag issues in the text that it will only explain to you if you sign up for the Editor Plus version, which costs $10/month monthly or $8.33/month if paid annually upfront.
GrammarCheck review—the basic grammar checker
GrammarCheck did not do as well as some of the better tools in our list but not as bad as the “low quality” ones: It corrected about half of the errors in our text, did not add new ones, but then redirected us to Grammarly for a “Deep Check” to “detect even difficult-to-spot writing mistakes”. It doesn’t require you to sign up and is very simple and straightforward to use—but its functions are very basic and some practical options seem to be missing.
Grammar check quality: medium
The tool fixed a significant number of errors in our text but completely ignored the rest. It seems only to be able to deal with very basic issues.
Usability and pricing
No sign-up is needed, just paste text in and click on “Free Check”. You can accept all suggested changes with one click, which can save you a lot of time. However, the “Deep Check” button just redirects you to Grammarly.
LanguageTool review—fixes spelling, punctuation, and word-choice errors
LanguageTool performed relatively well on our text, and was able to recognize most (but not all) spelling, word choice, and punctuation mistakes. However, it does take more than one click to correct an error, which makes the process a bit tedious, and there is no “fix all” function to compensate for that. The tool also identified some more issues that it wasn’t willing to explain to us unless we sign up for a Premium account. It does offer AI suggestions to rephrase sentences, but we found those unnecessarily extensive and a bit inconsistent in style.
Grammar check quality: medium
Most errors were identified and fixed but a few (even simple ones, e.g., a wrong article) were completely ignored, unless we asked the tool to paraphrase the whole sentence, in which case it made extensive (and often unnecessary) changes.
Usability and pricing
No sign-up is required to access the LanguageTool grammar checker, and getting started is quick and easy. The site has a clean user interface and offers a browser extension. Unfortunately, two clicks are needed to correct an error. To see some of the flagged issues, you need to sign up for the Premium version, which offers a Microsoft Office plugin and a customizable style guide. The Premium membership will set you back $59/year ($4.99/month), $39.90 per quarter ($13.30/month) or $19.90 month-by-month.
Ginger review—an academic grammar checker tool?
Ginger did not do very well on our text: It marked and corrected fewer than half of the errors and, more importantly, it only accepts very short pieces of text as input (450 characters) and seems to ignore whatever exceeds that (unless you purchase a Premium plan). This makes it not very useful for checking academic texts.
Grammar check quality: low
Ginger identified only a few of the errors in our text (at least in the free version; we did not sign up to see whether the Premium version offers more).
Usability and pricing
The tool comes with an extension, auto-inputs corrections, but a paid membership is needed to work on more than 450 characters (not words!). The Premium version promises a “fix all errors” function, a longer text character limit (5000), and translations into 40+ languages. It will cost you $6.99/month, $11.19/month, or $13.99/month for the annual, quarterly, and monthly plan.
Wordtune review—best AI tool for paraphrasing text
While Wordtune performed quite well in terms of the number of errors it found and corrected, it is in fact more of a paraphrasing tool than a standard grammar checker. Going through the mistakes one by one requires a lot of clicking and is a bit tedious, and there are no explanations whatsoever.
However, if you allow the tool to rewrite sentences completely, it will offer you a list of suggestions that sound great but can be quite far away from your original structure (and occasionally change the meaning of your text). We would therefore not recommend Wordtune for actual grammar checking, especially not for non-native and/or not very proficient speakers of English, but for authors with already advanced writing skills, it can be a great revision tool to improve the tone and flow of a draft.
Grammar check quality: medium-high
The grammar checker fixed most of the errors in our example text. Some suggestions altered the intended meaning of the text, and we therefore think Wordtune should only be used as a style tool for authors with a high English proficiency.
Usability and pricing
You need to create an account to use Wordtune, and the free version is somewhat limited. To “unleash the power of AI and take your reading & writing to the next level,” Wordtune offers you monthly plans of $9.99 for the "Plus" and $14.99 for the “Unlimited” version.
How We Conducted Our Reviews
As you can see in the screenshots included above, we compared the different grammar checkers by feeding them the same 150-word text that contained a number of grammar, spelling, word choice, and punctuation errors.
We also looked at overall usability, speed, how many clicks were necessary to implement a suggested correction, whether a sign-up was required to use all/some functions, and how clear and user-friendly the interface was.
Read our other AI tool reviews, including the Best Summarizing Tools, Best AI Tools for Research, and Best AI Essay Writing Tools on the Wordvice AI Blog.