One Writing Checker Is Never Enough – Here’s The Proof

I never trust one writing checker before I publish my writing online. I’ve learned the hard way that while it is quick and easy, none of them are perfect.

That’s why I am in the habit of using two or three before I trust my eyes for a thorough proofread.

It might seem pedantic, but meticulous checking of any form of writing before publishing is a vital step.

It’s hard enough to earn readers without losing them because of grammar, punctuation, and spelling mistakes.

How accurate is your writing checker?

Perhaps you pay for a premium grammar checker or rely on free tools.

I use a mix of both, but it always surprises me that the results are never the same. What one finds, another one misses.

Because I use these tools frequently, I have simply accepted the fact that I always need to use more than one writing checker.

However, I never stopped to consider which one is the most accurate. But finally, that’s what I decided to do.

For my test, I chose a short text of about 250 words, and intentionally made ten grammar, punctuation, and spelling mistakes.

Then I ran my text through six popular writing checkers, both free and paid.

The good news is that most of them performed reasonably well, but none of them were perfect.

It was also interesting that premium checkers didn’t perform better than free tools.

However, I have to take into account that my test was only a short text, and free tools usually have a limited word count.

So which writing checker is the best?

Testing six popular writing checkers

Here’s the text I used to check the accuracy of each tool.

The text is a mixture of short and very long compound sentences, which I think is a fair test.

You can see the ten intentional errors I have marked in bold red, which are a mix of grammar, punctuation, and spelling mistakes.

The real holiday bonus for me though was yet to come. 

It was on a quiet Sunday morning when I ventured out of our little holiday chalet to by some milk. Talk about being in the right place at the wrong time.

Just as I was to leave the corner shop with my milk, who should be leaving the newsagency about twenty metres away, but my literary hero, Erich von Daniken!

I skipped towards the newsagents, ready to buy a newspaper, which of course I wouldn’t have been able to read, seeing as though I don’t understand more than three words of German, but that would have been fine if it had managed to help me simply say hello, or even guten tag, to my literary champions. 

Sadly, my lucky wasn’t in, as my rather elderly literary hero was quite quick his feet for his age, and he was already back in his car with his Sunday morning newspaper before I could cover half of the necessary twenty metres.

Maybe it was the milk that slowed me down. I settled, though, on at least having sceen my hero, even if only from a distance.

With this glass half full or half empty achievement behind me, I satisfied myself in at least knowing that I had milk for my coffee and that my little holiday in Beatenberg had been worth while on the hero-worshiping, lucky sighting, and just missing chance of a lifetime by a whisker scale. 

You can see from the text that the ten errors are quite obvious, but are also ones that are easy to make when typing quickly.

How did the six checkers perform?

Reasonably well, as you will see. However, there were differences, and some surprises.

I used the desktop version (not a browser extension) for each test. Here are the results, and I have noted if I used a free or paid tool.

1. Grammarly (Premium)

As it is one of the most popular, I started with Grammarly.

To my surprise, it failed to detect five of the errors, which is not a great result at all.

You can see how the check performed in the image below.

Accuracy: 50%

2. ProWritingAid (Premium)

The result was an improvement on Grammarly.

However, it still missed three errors.

Accuracy: 70%

3. QuillBot (Free)

A similar result, but missing three different errors compared to the first two tests.

However, it did make some useful style and hyphenation suggestions.

Accuracy: 70%

4. LanguageTool (Free)

It missed four errors, but caught a possible problem with US or British spelling of metres.

But it did highlight the possibility that newsagency could be two words.

Accuracy: 60%

5. ChatGPT (Free)

It’s now very common for writers to use ChatGPT as a grammar and spelling checker.

All you need to do is use a prompt to ask for a grammar and spelling check, and paste in your text.

Depending on your prompt, you can sometimes get a list of errors or a revised text. In my test, it rewrote my text to include its corrections.

The result was surprisingly good, but it missed the article before, “missing chance”.

It was only one of two tools to spot the error, “I was to leave” and corrected it to “about to leave”. But more correctly, the clause should read “was leaving” as it makes the sentence parallel, and more sense in the context.

But it did correctly add an umlaut to the name, Däniken.

Accuracy: 90%

6. Google Gemini (Free)

Last one on my test list.

Gemini missed two errors: I was to leave, and the missing article in missing chance of a lifetime.

However, as you can see in the image, it failed to highlight some errors that it fixed. But I suppose that’s only a minor point.

Accuracy: 80%

The ten errors found or missed

Here’s a tally of the ten errors and the correction notes among the six tools.

Error 1. No commas around though. All six tools found this punctuation error.

Error 2: Misspelling of buy: by. Found by five tools, but missed by Grammarly.

Error 3: Grammar error: was to leave. For some reason, this obvious error was the most challenging for all six tools.

Only ChatGPT and Prowritingaid noticed the error. However, neither offered the right correction, which was the past continuous, was leaving.

Error 4: The word newsagents should be possessive. Only Gemini found this error and correctly changed it to newsagent’s.

Error 5: The word champions should be singular. Only ChatGPT and Gemini corrected this mistake.

Error 6: The word lucky is a typo. It should be luck. All tools except for Prowritingaid found this error.

Error 7: The missing preposition on, in quite quick his feet. Every tool found this mistake.

Error 8: A simple typo. The word sceen is an obvious spelling mistake found by all tools.

Error 9: Clearly, worth while, should be one word. Found by all tools apart from LanguageTool.

Error 10: The phrase, just missing chance of a lifetime, is clearly missing an article. This error was only found by Prowritingaid, Quillbot, and Gemini.

Conclusion

My first impression was that, for basic grammar, punctuation, and spell-checking, there was little difference between free and paid tools.

In fact, the free tools all performed better than Grammarly.

Another aspect is the difference in how each tool works. Some writers might prefer a standalone tool where you can tackle each error one by one.

However, AI writing checkers like Gemini and ChatGPT are all or nothing. You get a report or a revised text.

It’s up to you to decide how you prefer to work and which tools you select.

However, my tests show that none of these six popular tools are perfect, but some are a little better than others, including the free tools.

So, which one is the best writing checker? Judging from my tests, it’s clearly ChatGPT for accuracy. However, for a standard grammar and spell checking tool, perhaps QuillBot was a nose in front of the rest.

However, the real lesson is that you can’t rely on one tool. If you use two or three grammar checkers, you have a good chance of catching most errors.

But then proofread carefully, because no online grammar checker can replace your keen eyes, knowledge, and good judgment.

Related Reading: Perfect Grammar Will Not Make Your Writing Brilliant