/ 10
/ 10
/ 10
/ 10
/ 10


Accuracy Score
Premium Student Paper Test
Recommend Upgrade to Premium

Editing & Feedback

Correction Speed (seconds)
Additional Cost

Ease of Use

Mobile Version
Browser Extension
Upload Document


Subscription Pricing (monthly)
Browser (Chrome, Firefox, Safari)
Add Words Dictionary
Genre Specific Writing Styles


Grammar Tutorials
Live Chat

Best Online Grammar Checker

Why Use Online Grammar Check Services?

After using grammar checker extensions on the web and in my articles for over a month, I think Grammarly offers the best online editing application.  It detects the most errors and offers correct suggestions to fix them. I also found it to be the least invasive and glitchy of the software I reviewed.

Authors and creative writers just learning their craft should consider the text analyzer ProWritingAid because it checks for repetition and overused words and catches patterns in dialogue. It wasn’t the best at detecting punctuation or grammar errors compared to other software, but ProWritingAid gives the best content-related feedback and has the potential to vastly improve your writing. For example, it was great at finding sentences that needed a rewrite because of weak verbs. The free version of this program is pretty decent too, and it’s a good option if you’re interested in saving money.

If you’re looking for a cheaper alternative to Grammarly, you might give WhiteSmoke a try. It’s only $9.95, and while not quite as useful as our favorite grammar checkers, the service updates frequently, has a mobile app and uses similar text box technology as Grammarly.

Our accuracy scores for these products may seem a little low. For example, the top-performing product only earned a 60 percent in our tests. These scores are based on the average number of errors the grammar checker found in documents I compiled that contained common grammatical errors. We included this information because we want our readers to know that this software, while helpful, can’t catch every kind of grammar or syntax error yet.

Based on my experience as a professional writer and as a writing instructor at a state university, online grammar checker software is best for users who already have a working knowledge of grammar and punctuation. Occasionally, these programs give you bad advice, and some didn’t even have quality or accurate writing on their sites. So, if you’re a student, new to English or want to improve your language skills, you’ll want to find a different, more comprehensive tool to help you proof your documents. Before you trust these sites to edit your work, you need to be able to tell the difference between a good suggestion and a bad one.

Online Grammar Checker: How We Tested, What We Looked For


The best grammar checkers are sophisticated enough to accurately identify a variety of different problems in writing and offer appropriate suggestions for fixing any errors. In addition, I liked programs that let you customize their suggestions to match your genre and writing style – if you work in an industry that uses a lot of shorthand or job-specific vocab, its useful to be able to adapt the software to your needs.

I used previously graded assignments to see if the software could pick up on problems with grammar and content. After accepting suggestions, I rated how much each program improved the documents and gave it a grade.

Editing & Feedback

I also wanted to see which programs detect issues the fastest and how smoothly they worked when I typed at my normal speed. Time is important when choosing editing software because if you have to wait around for the program to analyze your work, you might end up sending content with errors you didn’t see, especially in messaging applications. Many of these programs are intended for English language learners, so I also checked how accurate the translation features are in the software that have them.

Because electronic composition has made it easier than ever to accidentally plagiarize material, I thought a plagiarism checker was a valuable addition to the software. I used material from our site to evaluate how good the checker is at identifying copied material.

Ease of Use

We all want our writing to be professional and free from errors, but software can quickly get expensive. That’s why I looked at products that provide the most value, and I favored those that give you more tools for less money.

Compatibility is important to consider when you select an online grammar checking extension. You want to make sure the grammar checker works well with the browser and word processor you prefer. Programs that offer more features and work on more websites are a better value. Some even work on mobile devices, so you can produce error-free writing online from your phone, and I gave those products higher scores.

Help & Support

If you’re a writer working with a deadline, 24-hour support can be incredibly helpful. I looked for services that provide instant access to help. Grammar checkers that have live chat support or provide email and phone contact information fared better in our rankings.

How We Tested

I researched the services’ claims about their software by installing the downloadable extensions on various browsers and websites to see if their editing suggestions were helpful. I also looked at each software’s features and how they differed in a premium versus a free membership. Using student and professional papers, I checked each listed tool to see if it worked. I used the error detection in Microsoft Word as a baseline and was not surprised to find that most grammar checkers do a better job than this popular word processor.

I signed up for each grammar checker service and composed sentences and documents with errors to test whether the software could find them all. In addition to looking for typical grammar and punctuation errors, I tested to see if the programs could pick up more subtle and complicated errors.