7 Best Comma Placement Checkers

Tripping over English comma rules can muddy your message, but online comma placement checker tools can help you write clear and error-free prose. 

Misplaced commas can cost you anything from intense embarrassment to millions of dollars. That’s no exaggeration. A company in Portland, Maine once had to pay $5 million in penalties and court fees because they left one little comma out of their employment contracts.

Fortunately, you can avoid comma errors if you know a few simple rules and use a reliable punctuation and comma placement checker on all your writing projects.

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$30 per month
$79 per year
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Comma placement checker

Each of the following online punctuation and grammar checkers has strengths and weaknesses. They will all help you fix comma errors, grammatical errors, spelling mistakes and sentence structure. Most of them have a free version, and options to pay for premium features geared toward professional writers.

Which artificial intelligence proofreader tool is best for you? 

1. Grammarly

Pricing: Free/$30 per month/$139.95 a year

Grammarly business grammar checker
Here you see Grammarly revising sentences

Grammarly is a great, full-featured comma error checker, spell checker, and grammar checker that will help you nix spelling errors, punctuation mistakes and make suggestions to avoid grammar errors. Its Chrome extension is free and helps you stick to grammar rules. Its paid platform also catches plagiarism gaffes. 

Of all the tools we tried, Grammarly caught the most errant and missing commas/

Read our Grammarly review

Here, you can see the Grammarly comma checker in action
Best AI writing assistant
From $12 Per Month

We tested dozens of grammar checkers, and Grammarly is the best tool on the market today. It'll help you write and edit your work much faster. Grammarly provides a powerful AI writing assistant and plagiarism checker.

Become a Writer Today is reader-supported. When you buy through links on our site, we may earn an affiliate commission.

2. ProWritingAid

Pricing: From free/$70 a year

ProwritingAid grammar checker
ProWritingAid has several useful reports for writers

This robust English grammar, style, spelling, and punctuation checker integrates with Microsoft Word, Outlook, WordPress, Gmail, Google Docs and other writing tools geared toward professional writers. You can use the basic sentence checker features for free, but they include more features if you want to pay for them. 

ProWritingAid caught some errant commas but not as many as Grammarly. Read our ProWritingAid review

Here, you can see ProWritingAid flagged a comma for review
20% OFF
$3̶0̶ $24 per month

ProWritingAid is a powerful, accurate grammar checker and style editor. It's suitable for non-fiction and fiction writers and doesn't require a monthly subscription. Save 20% per month or year.

We earn a commission if you make a purchase, at no additional cost to you.

3. Ginger

Pricing: $13.99 per month

The Ginger grammar checker
Ginger grammar checker also has a translator with more than 50 language options

Ginger helps you proofread fast for grammar, spelling, and punctuation errors with its standard proofreading tools. In addition to helping you hone your writing skills, it has a translator with more than 50 language options. It doesn’t have a plagiarism checker, however. Ginger lacks the accuracy of ProWritingAid and Grammarly.

Read our Grammarly Ginger comparison to find out why

Ideal for Non-English Speakers

Ginger is a popular alternative to Grammarly. Although it doesn't have as many features, it's relatively accurate and affordable. It's also useful for non-english speakers.

We earn a commission if you make a purchase, at no additional cost to you.

4. Whitesmoke

Pricing: $6.99 per month

Whitesmoke proofreader
This is your go-to app if you really just need a punctuation checker tool

For $5.00 a month, Whitesmoke is an affordable tool will help you eliminate common comma splice errors and many less-common punctuation mistakes, including semicolon use. However, the user interface isn’t as polished as Grammarly. And it lacks many reports present in ProWritingAid. We tried Whitesmoke for a few weeks before going back to Grammarly and ProWritingAid, due to ease of use.

5. PaperRater

Pricing: Free

PaperRater grammar checker
PaperRater checks spelling, typom apostrophe and grammar using artificial intelligence

PaperRater is free and premium web-based spelling, typo, apostrophe and grammar checking tool. It uses artificial intelligence to help you root out comma errors. It also checks for plagiarism and gives your writing a readability score with ideas of how to improve. You can check five pages for free via the online submission form. It’s powered by Ginger so expect similar accuracy. In our tests, PaperRater missed some issues that Grammarly caught. However, it’s free.

A PaperRater report

6. LanguageTool

Pricing: $5 per month

LanguageTool grammar checker
This open-source punctuation corrector is compatible with Microsoft Word, Chrome, Google Docs, Firefox and LibreOffice

Not only does Language Tool do a great job of checking grammar and punctuation in English, it does the same for several other languages. This open-source punctuation corrector is compatible with Microsoft Word, Chrome, Google Docs, Firefox and LibreOffice. It’s faster than PaperRate and flagged up some missing commas.

A Language Tool comma placement report

7. Writer.com

Pricing: $11 per month/$99 per year

Writer.com grammar checker
This app also evaluates writing style, tone, readability, brand voice and terminology geared for your audience

Writer.com is beyond just a great comma splice fixer. Designed for professional writers, it uses artificial intelligence and natural language algorithms to root out punctuation errors, particularly comma placement errors.

It also evaluates writing style, tone, readability, brand voice, and terminology geared for your audience. It’s comparable to Grammarly, except for business writers.

What are the Rules for Comma Placement?

Of course, it’s wonderful to have all of these punctuation, spelling, grammar and comma placement checkers available in various formats. You’re sure to find one that fits your needs as a blogger, email marketer, web designer, student, professor, teacher or anyone else who needs to write clearly.

However, nothing can replace a basic, personal knowledge of comma usage rules. 

Don’t Use Commas with “That”

Avoid using a comma before “that” in a restrictive clause. Using “that” tells the reader that the information connected to the first clause is essential. 

  • Wrong: I dislike salads, that contain arugula. 
  • Right: I dislike salads that contain arugula. 

You should, however, use commas before “which” because they add interesting, but non-essential information to the sentence. These clauses often act like parenthetical phrases, so you will want to add a comma after the clause as well, as shown below: 

  • Wrong: The boys’ sweater which his brother gave him scratched his neck. 
  • Right: The boy’s sweater, which his brother gave him, scratched his neck.

Do Use Commas Between Two Independent Clauses Joined by a Coordinating Conjunction

First, remember that the coordinating conjunctions are “FANBOYS” (for, and, nor, but, or, yet, so). Coordinating conjunctions can join two independent clauses that could be their own sentences if you separate them with a period. Here are some examples: 

  • Wrong: I love bread but I have a gluten allergy.  
  • Right: I love bread, but I have a gluten allergy.
  • Wrong: It was snowing outside so I put on my boots.
  • Right: It was snowing outside, so I put on my boots. 

Don’t Use Commas Before Verbs in Relative Clauses 

Always ask yourself if the information that you’re adding in a clause is essential to the meaning. In the case below, the comma breaks up the essential connection between “is” and the best thing. So you would leave out the comma here: 

  • Wrong: One of the best things about using a grammar checker, is getting an error-free blog. 
  • Right: One of the best things about using a grammar checker is getting an error-free blog. 

Avoiding the Comma Splice 

Some sentences should really be split into two sentences to avoid dreaded comma splice errors. If you have two independent clauses, but you don’t have a coordinating conjunction to connect them, just use a period: 

  • Wrong: I forgot to use an oven mitt, I burned myself
  • Right: I forgot to use an oven mitt. I burned myself
  • Also Right: I forgot to use an oven mitt, so I burned myself. 

Commas and Dependent Clauses

If a dependent clause (one that cannot be its own sentence) comes before an independent clause in a complex sentence, you need a comma as shown here: 

  • Wrong: After we ate dinner at the restaurant we went for a walk along the river. 
  • Right: After we ate dinner at the restaurant, we went for a walk along the river. 

On the other hand, if you put the dependent clause in the second position after the independent clause, you can drop the comma like this: 

  • Wrong: We went for a walk along the river, after we ate dinner at the restaurant. 
  • Right: We went for a walk along the river after we ate dinner at the restaurant. 

Why You Can Trust Us

I’ve written and published dozens of articles for newspapers, magazines and online publications including, Forbes and Lifehacker. I’m also a best-selling non-fiction author, a trained journalist and a copywriter.

Software like the options here forms a key part of my writing workflow for non-fiction. I use these types of software regularly to improve my work and also to check work by freelance writers who publish content on this site.

Our Testing Criteria

We regularly update this roundup of comma checkers as the product evolve. We test new features by checking articles, book chapters and blog posts for grammatical mistakes and other issues. These articles and other writing samples range from several hundred to several thousand words in length. Typically, we test them using the web, desktop and browser apps and plugins.

The Final Word on Comma Placement Checkers

Even experienced writers need all the help they can get to fix comma errors that could ruin the meaning of sentences. For example, consider how the comma (or lack thereof) completely alters the sentence below: 

  • Let’s eat, Jenny. 


  • Let’s eat Jenny. 

Commas save lives! If you aren’t sure if your comma placement is correct, it behoves you to avail yourself of at least one comma usage checker mentioned here. Some of them excel more as grammar checkers and punctuation checkers, while others also scan for plagiarism and language usage.

At the very least, get the free version of Grammarly and watch how much it helps you improve your comma usage and clarifies your writing. If you have a bigger budget, use either ProWritingAid or Grammarly Premium.

Want more? Check out our guide about when to use comma with examples.

FAQs About Comma Placement Checkers

Is there a free punctuation checker? 

Yes, many of the grammar and punctuation checkers listed here have a free tool. Grammarly, ProWritingAid, Ginger and LanguageTool all have free versions or trials enabling you to try their features. 

What is the best free grammar checker?

All the tools listed above will catch grammatical mistakes, but they each have different features available in their free versions. For example, Grammarly has a very robust free version that should take care of most of your grammar checker needs. 

How do you check if a sentence needs a comma?

If you are struggling with comma usage, you can copy and paste the sentence into one of the comma placement checkers listed above for free. They should catch any comma errors you’ve made.

  • Bryan Collins is the owner of Become a Writer Today. He's an author from Ireland who helps writers build authority and earn a living from their creative work. He's also a former Forbes columnist and his work has appeared in publications like Lifehacker and Fast Company.