6 Calculators for Grammar and Writing

Reading Time: 4 minutes

Calculators for grammar and writing?

Financial calculators help you to determine payments for a house or car or balance your checkbook. Use this calculator for nutrition facts and calorie counts for thousand of products. Want to know your dog’s age in human years, this site will calculate it.

But what about writing? A simple calculator can count the number of words you wrote. But what else is there to calculate in writing?

Turns out, there’s a lot. Grammar and writing calculators can

  • determine the percentage of passive sentences,
  • analyze the reading level of a document,
  • count the words in a sentence,
  • calculate the average word length,
  • let you know the number of unique words used.

Why wait? Let’s get started calculating.

Passive Voice Detector Calculator

Writers are advised to avoid using passive voice. While avoiding passive voice altogether is almost impossible by writers, an article, blog post, or research paper should not have more than 20% passive voice.

The Passive Voice Detector detected that one of the above sentences (50%) used passive verbs, and if the rest of the blog contained such a high percentage, the writer (me) needs to revise it.

In case you need a quick review of passive versus active, in this sentence

The blog post was analyzed by the Passive Voice Detector.

the thing performing the action (the detector) is not the subject of the sentence.

If the sentence is rewritten like this

The Passive Voice Detector analyzed the blog post.

The actor (the thing doing the analyzing) is the subject of the sentence.

So how can you check for active and passive voice? You can identify the verb in each sentence (which will take forever), or you can go to the Passive Voice Detector, copy and paste some text, and let it do the work for you.


You will like the simplicity of this calculator. The directions are clear and the analysis is quick and accurate.

Free Readability Calculator

If a blogger or writer wants to know a post’s reading level, try the Readability Formula tool.

The tool lets you paste a writing sample from 200 to 3,000 words. I pasted a section from a post about semi-colon tattoos. The majority of the indexes scored it in the 6-8th grade range.

For fun, I pasted a few paragraphs of a post about grammar nerds, and my readability scores were in the 6th and 7th grade.

One of the reasons you might like this tool is it calculates more than one index to give me an average reading level. This site has a few ads, but they are unobtrusive. Two tips:

  • Paste your words as plain text
  • Check the I’m a human box at the bottom

Count Wordsworth

Kids love dinosaurs, so I used a section from the British Natural History Museum on dinosaurs for this calculator for grammar and writing. The Count did his thing, and I learned that it had the following metrics:

  • an average of 18.25 words per sentence
  • 23 prepositions
  • 5.10 letters per word
  • approximately 31 syllables per sentence.
  • the third most popular word is dinosaur

I enjoy this calculator, but it is more of a novelty and not as useful as the others. One odd quirk is that after you enter the text, the first piece of data is 0 words per sentence. Scroll down for the actual counts.


Lettercount–So Your Pinterest Post Won’t Be too Long

Tweets have a character limit, and so do other sites. A LinkedIn summary needs to stay under 2,600 characters, your Instagram post can’t be over 2,200, the Pinterest post is limited to 500, and Snapchat has a 250 character limit.

If you need to shorten a post, copy and paste it into Lettercount, a simple tool that counts how many characters are in the text.

The site has a detailed article about character length and its importance. People sometimes confuse letter and character length. A sentence with a character count of 29 will have a longer character length. How is that possible?

In counting character length, spaces count. My question has 18 letters (counting the question mark), but 21 characters when the spaces are added in.

Planet Calc–When You Want to Know if You Are Repeating Yourself


Sometimes it feels like we are using the same words again and again. If you think that might be the case, PlantCalc will let you know. I pasted this section in the Unique Word Calculator. Out of 140 words, 93 are unique. Repeated words include “the,” “of,” and “you,” which are unavoidable.

You will appreciate the simplicity of this calculator. Some repetition is good, but your reader will notice if you use too much. This is one of my favorite calculators for grammar and writing.

Ink For All–Parts of Speech Calculator

Sometimes you need to know what part of speech in a sentence, especially if you are in an English class. The Inkforall site claims to do so.


However, it is not 100% accurate, especially with verbs. I pasted a paragraph, and the tool labelled the word writing in the phrase “grammar and writing calculators” as a verb. It also failed to recognize an infinitive, and didn’t recognize the verb “is” in there’s.

It did get most of the other words correct, however.

Unfortunately, InkforAll has transformed itself into a full-service AI writing tool. Results are only revealed after the user signs up with Google, Facebook, or Microsoft.

Update for Bloggers and Webmasters

Datayze, the parent site of Passive Voice Detector, offers several webmaster tools, including a thin content checker that crawls a site for each page’s word count. Other features include a website validator that looks for common mistakes, a tool to analyze the navigability of your site, and a readability analyzer for the average site’s readability.

Our article 5 Writing Tips Every Writer Should Know provides helpful writing guidance.

calculators for grammar and writing
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