Nobody Talks About Sentence Count — But They Should
Every writing guide on the internet talks about word count. Some talk about character count. Almost nobody talks about sentence count. And that is a problem, because the number of sentences in your writing — and more importantly, the average length of those sentences — is one of the most direct measures of how readable your content actually is.
I discovered this after a writing coach looked at one of my articles and pointed out that my average sentence length was 38 words. The recommended maximum for easy online reading is 20 words. My readers were not bouncing because my content was bad. They were bouncing because reading it felt like hard work.
This tool counts your sentences so you can start paying attention to something most writers completely ignore.
What This Tool Measures
Paste any text and instantly see your total sentence count alongside word count, character count, and paragraph count. Use the sentence count alongside total word count to calculate your average sentence length — the single most useful writing metric most people have never checked.
Average Sentence Length — The Formula That Changed My Writing
The calculation is simple:
Average Sentence Length = Total Words ÷ Total Sentences
Here is how to read the result:
Under 14 words — Very easy to read. Suitable for news articles, mobile content, social media, and audiences who are reading quickly or in a second language. Can feel choppy if overused.
14 to 20 words — The sweet spot. Easy to read, flows naturally, suitable for most blog posts, general audience articles, and marketing copy. This is where most good online writers land.
20 to 25 words — Acceptable for more detailed or technical content. Readers need to focus slightly more. Works in long-form guides where depth is expected.
Over 25 words — Getting difficult. Readers have to hold more information in their head to reach the end of the sentence. Bounce rates tend to rise. Academic writing often lands here, but most online writing should not.
Over 35 words — This is where I was before I fixed my writing. Sentences this long are genuinely exhausting to read on a screen. If your average is above 35, shortening your sentences will improve engagement more than almost any other change you can make.
Why Sentence Variety Matters as Much as Sentence Length
Short sentences are not automatically better. Writing made up entirely of short sentences sounds robotic and feels unnatural to read. The goal is not to make every sentence short — it is to vary your sentence length intentionally.
Short. Then medium length that gives more context and flows into the next idea. Then a longer sentence that builds a complete argument or paints a full picture before landing on its conclusion. Then short again.
That rhythm is what makes writing feel alive. Sentence count helps you see your patterns so you can break them when they become monotonous.
Five Types of Writing and Their Ideal Sentence Counts
Blog post (1,000 words) — Aim for 60 to 80 sentences. Average sentence length of 13 to 17 words. This creates an easy, flowing read that holds attention through to the end.
Email newsletter (300 words) — Aim for 20 to 30 sentences. Short sentences work especially well in email because people read email even faster than they read blog posts.
Product description (100 words) — Aim for 6 to 10 punchy sentences. Every sentence should either describe a benefit or answer an objection. Nothing else earns its place here.
Social media caption (Instagram / LinkedIn) — 3 to 8 sentences for most posts. The first sentence is the most important because it is the only one that shows before the “more” button cuts off.
Academic or technical writing — Sentence length rules are more relaxed here because the audience expects and accepts complexity. Average sentence lengths of 20 to 28 words are common and appropriate. Much longer than that still hurts readability even in academic contexts.
How I Use Sentence Count When Editing
My editing process has three steps that all involve sentence count.
First, I check the total sentence count against the total word count to get my average sentence length. If it is above 20 words, I go through the piece looking for long sentences I can split into two.
Second, I look for sections where I have written five or more sentences in a row at roughly the same length. That is usually a sign the writing has gone flat. I rewrite to create more variation.
Third, I check my opening paragraph specifically. The first three sentences of any article determine whether someone reads on or leaves. If my opening sentences average over 20 words, I rewrite them to be shorter and more direct.
Frequently Asked Questions
How does the tool count sentences?
The tool counts sentences by detecting ending punctuation — full stops, exclamation marks, and question marks. It is accurate for standard English prose. Sentences without closing punctuation, bullet points, and headings are not counted as sentences.
What is a good average sentence length for blog posts?
For most general audience blog posts, an average sentence length of 14 to 20 words is ideal. This is readable without feeling too simple, and it keeps readers moving through your content without fatigue.
Does sentence count matter for SEO?
Sentence count affects readability scores like the Flesch Reading Ease score, which some SEO tools use to evaluate content quality. More practically, shorter sentences reduce bounce rate and increase time on page, both of which are signals Google uses to evaluate content.
Is this tool free?
Yes, completely free with no word limits, no account required, and no usage restrictions.
Does it work on mobile?
Yes, the tool is fully responsive and works accurately on all devices.
The One Number Most Writers Have Never Checked
Take any piece of writing you have published recently. Paste it into this tool. Divide total words by total sentences. That number is your average sentence length.
If it is under 20, your writing is in good shape. If it is over 25, you now know exactly what to fix — and fixing it will make a noticeable difference to how long people stay on your page.
Most writers spend hours on headlines and SEO keywords while never once checking the metric that most directly affects whether people actually finish reading what they write.
Now you have the tool. Use it.