ProWritingAid vs. Grammarly: Which app should you use?

Everyone's a writer in some shape or form. Whether sending a message, posting a social update, sharing your opinion, or publishing a novel, we communicate through writing. Often we don't think twice about how we write, which sometimes leads to miscommunication. But other times, we know that our writing needs to be spot on. 

Aside from hiring an editor, you can use apps to check your spelling, grammar, and punctuation. And you can go even deeper with AI grammar checkers and rewording tools like Grammarly and ProWritingAid. These apps can also check your intent, tone, and style to ensure you deliver the right message.

I've tested and written about Grammarly and ProWritingAid previously. And although I've used Grammarly almost daily throughout my writing career, I was keen to see how the two apps fared in a direct comparison. So, for this article, I signed up and tested each platform. I spent time running various scenarios to see how they stacked up against each other. And here's my verdict.

• Grammarly is slightly easier to use

• Both apps offer extensive customization options 

• ProWritingAid wins hands-down on analysis reports

• Grammarly has better rephrasing tools

• Both apps integrate nicely with other platforms

• Grammarly has a better free plan

Grammarly vs. ProWritingAid at a glance

Here's a quick comparison table to get you started, but keep reading for details about the various features and my experience using each app. Or you can scroll to the end for a quick summary of which AI grammar checker will be best for you.

A quick word about accuracy

Both of these apps are running on top of large language models (LLMs)—they're not trained identically, but the accuracy will be subjective no matter how you slice it. Here are a few examples highlighting the quirks in accuracy.

Both apps flag different unknown words or misspellings. For example, ProWritingAid flags "underworked" as a misspelling and suggests "under-worked" as a replacement. 

Grammarly, on the other hand, thinks it's spelled correctly:

(And I'd be inclined to agree. As does Merriam-Webster.)

Sometimes, though, the apps agree. Take this sentence, for example: "Now that you know about Asana's work management features, you might be wondering what you should look for when choosing a work management tool." Both apps think it might be unclear and suggest changing "you might be wondering what you should" to "you might wonder what."

All this goes to show that, although these apps are great, you have to question and check anything that looks untoward. Don't go accepting every suggestion from either app.

And because it's subjective in any case, I'm going to focus on the features of the apps, not the accuracy of the suggestions.

Grammarly is slightly easier to use

Grammarly and ProWritingAid are available in various flavors, including desktop, mobile, web browsers, apps, and plugins. More on these later—for now, I'll focus on the web apps.

Here's Grammarly's editor.

And here's ProWritingAid's editor.

In my opinion, Grammarly has a cleaner, less-cluttered interface (although you can hide the top and side menus in ProWritingAid). Both apps highlight errors in-line, and in terms of using and accepting suggestions, there's not much difference between the apps. You work through the document, and accept or ignore the recommendations.

One niggle with ProWritingAid: every time you switch reports, like going from grammar to style, it recalculates all the real-time errors again (top left), which seems excessive. And one time, it froze completely when renaming a file.

Grammarly, on the other hand, toggles instantly. 

So, overall, even though it's a subtle difference, I found Grammarly more stable and slightly easier to use than ProWritingAid.

Both apps offer extensive customization options

Grammarly and ProWritingAid both have loads of customization options, which is especially important in a business setting. You can add a personal dictionary, for example, and customize the editor settings to fit your writing preferences. There's an extensive range of options on both, including things like:

• Use consistent capitalization

• Use a consistent style of abbreviation

• Avoid using very complex sentences

• Avoid using the passive voice

• Avoid using clutter words

In ProWringAid, you check the boxes and select the dropdown option, though it gives you a little more flexibility in terms of where the customizations are implemented. You can see in the screenshot below, for example, that the passive voice checker is turned off for documents categorized as academic papers.

On Grammarly, you can apply broad-strokes goals to each article (more on that in a bit), but you toggle the settings on and off universally. 

They also differ a bit in how they apply the rules. ProWritingAid seems more rigorous. For example, it flags this sentence as complex.

Whereas Grammarly doesn't, for the same sentence.

Again, just because the app suggests a sentence is complex, doesn't mean it is. The AI algorithms make their recommendations based on their vast training data. You should have a clearer idea of what your audience can handle—it's just that ProWritingAid seems to follow its rules more closely.

Back to those goals I mentioned: before you begin editing your work, both apps let you set goals for the piece, so the algorithms make valid suggestions. For instance, you wouldn't apply academic writing rules to your social media posts.

Grammarly offers four writing goals—domain, intent, audience, and formality—to tailor your writing suggestions, which you can set at the start of each piece.

ProWritingAid has more refinement on the domain. For example, you can select general, long, or short web content (and there are more types of writing to choose from), but doesn't include the other goals.

One isn't necessarily better than the other—it's just a matter of whether it offers what you're looking for as a writer.

ProWritingAid wins hands-down on analysis reports

Part of why ProWritingAid has a bit more of a learning curve is that it focuses heavily on reports covering grammar, style, readability, consistency, and plenty of other things.

You can get reports on almost every aspect of your writing. Things like:

• Repetition

• Vague wording 

• Sentence length variation

• Over-dependence on adverbs

• Passive voice

• Over-complicated sentence constructions

… and many more. Just take a peek at the screenshot above.

The idea here is that you'll become more aware of the mistakes that you make and be able to take steps to fix those problems and become a better writer—it's like having a real-life writing coach working beside you. 

For example, you can use the Sentence Length Check report to see where you have lots of long sentences—or too many sentences around the same length. Then take steps to vary the sentence length throughout your document and keep readers engaged.

And the next time you write, hopefully you'll be thinking more about sentence length, so you can nail the report this time around.

Grammarly takes a more conservative approach. You can click on your overall performance score in the right-hand menu, and download a PDF report for further analysis, but it's nowhere near as extensive as the ProWritingAid reports.

Grammarly has better (beta) rephrasing tools

Both apps currently have beta versions of their rephrasing or rewriting tools.

GrammarlyGO is Grammarly's new generative AI tool, which includes rephrasing. Simply highlight your text and click the pen icon for suggestions to improve it.

You can also select to shorten it, make it assertive or more confident, and many more variations, which you can see in the screenshot below. 

In ProWritingAid, if you select the rephrase tool from the top menu, it underlines every sentence that can be rephrased—100% in this example—and you choose which sentence you want to tackle.

(To me, that looks a little overwhelming. In effect, it's offering to rewrite the entire document. Imagine if you had a 50,000-word novel to trawl through!) 

When you select a sentence, ProWritingAid suggests four or five alternatives. But there are no further options like Grammarly to tailor the rephrasing.

So, in their current state, I'd say Grammarly's rephrasing tool is more beneficial and practical than ProWritingAid's.

Both apps integrate well with other platforms

Although neither app integrates directly with Zapier, both work with other tools through multiple desktop and mobile platforms, web browsers, apps, and plugins.

Depending on your writing needs, there's definitely a case for using the integrations over the standard editors. For example, checking and enhancing an email or social media post with the browser extension is much quicker than copying and pasting text into the main app editor.

Grammarly works across 500,000+ apps, websites, browsers, and devices, checking grammar, spelling, punctuation, clarity, conciseness, and adjusting tone. 

• Grammarly for Mac and Windows works on apps, word processors, email clients, and social media platforms, including Gmail, Outlook, Mail, Teams, Word, Notion, LinkedIn, Slack, Discord, and Salesforce. It also works in some browser apps, such as Gmail, but not Google Docs.

• Grammarly browser extensions for Chrome, Safari, Firefox, and Edge provide real-time writing suggestions on Gmail, Google Docs, Twitter, LinkedIn, and everywhere else you write online.

• Grammarly Keyboard integrates with your iOS and Android mobile apps to improve tone and eliminate mistakes in every email, message, and post you write.

ProWritingAid doesn't have a mobile app, but it does work with thousands of tools.

• ProWritingAid Everywhere for Windows and Mac provides suggestions for numerous desktop apps, including Outlook, Word, PowerPoint, Mail, Pages, Evernote, LibreOffice Writer, Scrivener, Slite, Slack, Discord, and WhatsApp. 

  • Note: Beta for Mac doesn't fully support all apps yet. For example, Word only checks text in the currently visible window.

• ProWritingAid browser extensions for Chrome, Safari, Firefox, and Edge provide real-time spelling and grammar checks in Gmail, Google Docs, WhatsApp, and more.

  • Note: The Google Docs add-in works better than the browser extension.

Both apps provide an API, so developers can bring real-time writing support to their software.

Grammarly has a more generous free plan (its paid plans are pricier but include a plagiarism checker)

At first glance, ProWritingAid's pricing plans appear more competitive, but there's a twist in the tale. Here's the score:

• Both apps offer a free version that provides basic writing suggestions. ProWritingAid restricts usage to 500 words and 10 rephrases per day, while Grammarly has no restrictions and also includes tone detection.

• For serious editing, you need the premium plans, and ProWritingAid has some great options. Although both apps start at $30/month, ProWritingAid has attractive $120/year or $399/lifetime packages. Grammarly is pricier at $60/quarter or $144/year.

• But bear in mind that Grammarly's paid plans already include a plagiarism checker. Whereas with ProWritingAid, you'll need to purchase plagiarism checks as an add-on starting from $10 for 10 checks.

Suppose you want team plans for your business. In that case, Grammarly is slightly more expensive at $15/member/month (minimum 3 members) than ProWritingAid at $12/user/month (minimum 2 users). Both apps offer licenses for academic institutions, and individual students can also get 20% off ProWritingAid.

Grammarly vs. ProWritingAid: Which should you use?

After spending significant time testing Grammarly and ProWritingAid, I can confidently say that both of these apps are excellent—it's just a case of deciding which one meets your requirements.

Choose Grammarly if you want to:

• Work in a less-cluttered interface

• Generate better rephrasing suggestions

• Integrate with more apps, including mobile

Choose ProWritingAid if you want to:

• Analyze more comprehensive writing reports

• Take advantage of better pricing options, including lifetime deals and student discounts

• Receive more granular, rigorous suggestions

I can see the appeal of both apps, and there's a case for using them both to ensure you catch everything. If I were managing a team of writers or writing more academic pieces, I'd consider moving to ProWritingAid. But for now, I'm happy staying with Grammarly—I'm familiar with it, and it does what I need.

Related reading:

• The best AI productivity tools

• The top AI text generators

• 8 ways real businesses are using AI for content creation

• How to write better