You've seen the tag at the top of almost every blog post and Medium article: "7 min read." It looks like a measurement, so it's easy to trust it the way you'd trust a word count or a file size. It isn't a measurement. It's a guess built on one average applied uniformly to every reader, every topic, and every sentence structure, which is why it's so often wrong for the specific thing you're about to read.
Where the Number Actually Comes From
Most reading-time estimates work the same simple way: count the words in the text, then divide by an assumed reading speed in words per minute. That assumed speed is usually somewhere in the 200-250 words-per-minute range, based on studies of average adult silent reading speed in English. Divide the word count by that number, round up, and you get the minutes shown in the tag.
The math itself is fine. The problem is the single number doing all the work. A 1,000-word article divided by 200 wpm gives you 5 minutes. That's a clean, confident-looking number. It just isn't your 5 minutes, or anyone's in particular -- it's an average smeared across a huge range of real reading speeds.
Why Your Actual Speed Can Be Wildly Different
Research on reading speed consistently finds huge variation between individuals -- some readers comfortably exceed 300 words per minute on familiar material, while others read well under 150 wpm, with no difference in comprehension. Age, reading experience, fluency in the language, and how much the topic overlaps with what you already know all move that number significantly.
Content itself matters just as much as the reader. A paragraph of plain narrative prose reads much faster than a paragraph dense with technical terminology, unfamiliar names, numbers, or code. A tutorial full of configuration flags and command-line examples will take noticeably longer to actually absorb than the same word count of casual opinion writing, even though a word-count-based calculator treats them identically.
Skimming vs. Reading Aren't the Same Activity
A reading-time estimate also assumes you're reading every word in order, start to finish, which is often not what's actually happening. A lot of real-world "reading" is scanning: jumping to headings, looking for a specific answer, skipping the parts you already know. Someone skimming a how-to guide for one specific step might spend 30 seconds on a page tagged "6 min read," and that's not a failure of the estimate -- it's just a different task than the one the estimate was built for.
The reverse happens too. Dense technical writing, legal text, or anything you're reading to actually retain (studying for an exam, reviewing a contract) gets read far slower than casual scanning, often with re-reading of the same paragraph. A flat wpm number has no way to account for that.
What These Estimates Are Actually Useful For
None of this makes reading-time estimates useless -- it just means they're better suited to a narrower job than people assume. They're genuinely helpful for:
- Comparing the relative length of two pieces of your own writing before you publish either one
- Deciding whether a draft has drifted too long for what it's trying to say
- Giving readers a rough sense of commitment before they click, the same way a video's duration does
- Checking whether an email, announcement, or internal doc is reasonable in length before you send it
What they're not good for is predicting exactly how long it will take you to read something, especially technical or unfamiliar material. Treat the number as a length indicator, not a stopwatch prediction.
Checking Your Own Writing
If you write regularly -- blog posts, documentation, newsletters, product descriptions -- it's worth running your own drafts through a reading-time estimate before publishing, not to trust the exact minute count, but to catch pieces that have quietly grown much longer than you intended. A draft that comes back at "14 min read" when you were aiming for a quick update is a signal to cut, even if your actual readers will all finish it at different speeds.
You can paste any draft into the Reading Time Calculator to get an instant estimate based on word count, useful as a rough length check even though the exact minutes will never match every reader equally.