How to Measure Topical Coverage and Find Content Gaps
Check your content against a list of subtopics, spot what is missing and turn the gaps into a writing plan.
A page can be well written and still miss the point. If people searching your topic expect to learn about cost, time, tools and common mistakes, and your article covers only the first two, a more complete competitor will usually win. Topical coverage is a way to measure completeness โ and the gaps it reveals are often the quickest content wins available.
Here is how to use the free SeoSpidie topical coverage calculator to check a page or a whole section.
Step 1: Build your subtopic list
Start with a specific topic, not a broad category โ "terrace vegetable gardening in hot climates" rather than "gardening". Then list the subtopics a complete answer should cover. Good sources: the headings used by the top-ranking pages, "People also ask" questions, related searches and the questions your customers ask. For the terrace garden example, the list might include container size, potting mix, watering in summer, shade nets, best vegetables, pests and weight on the roof.
Step 2: Add your content
Paste the subtopics into the calculator, one per line, and paste the text of the page you want to measure. For a section of your site, paste all the posts on the topic together so you can see how well they cover it as a group.
Step 3: Read the coverage result
The calculator marks which subtopics your content covers and which it does not, and gives an overall coverage figure. Treat the figure as a guide rather than a grade. What matters is the list of uncovered subtopics.
Step 4: Sort the gaps
Not every gap needs filling. Sort them into three groups:
- Add to the existing page โ closely related points a reader would expect in the same article. A short section or a few paragraphs is enough.
- Write a new page โ subtopics big enough to deserve their own article, with their own search intent. Link them to and from the main page.
- Ignore โ subtopics that are off-target for your audience or that you cannot cover honestly.
Step 5: Compare with what ranks
Open the top results for your main search and note the subtopics they cover. If all of them explain something you skipped, that is a strong sign readers expect it. If only one does, it is optional. The competitor comparison tool helps you compare headings and structure side by side.
Step 6: Fill gaps with substance
Adding a subheading and two generic sentences does not close a gap. Answer the subtopic properly, with examples, numbers or experience where you have them. One genuinely useful section is worth more than five token ones, and padded content can make a page less helpful overall.
Why coverage matters for AI search too
AI answers in Google and in chat assistants pull together information from pages that answer specific sub-questions clearly. Pages that cover a topic completely, with clear headings for each subtopic, give these systems more to cite. Read how to optimize content for Google AI Overviews for more on that side.
For the bigger strategy behind coverage, see how to build topical authority for a new website.
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Frequently asked questions
What is a good topical coverage score?
There is no universal target, and the score depends on the subtopic list you supply. Use it to compare versions of your own page over time, and focus on the specific gaps it lists.
Should I make one huge page that covers everything?
No. Cover closely related points on the main page and give bigger subtopics their own articles, linked together.
How often should I check coverage?
When you plan a new article, and when an existing important page starts losing rankings.
Is the calculator free?
Yes, with no sign-up.