How to Do a Content Gap Analysis With Semrush (Step-by-Step)

Content gap analysis isn’t about finding every keyword you’re missing — it’s about finding the right keywords your competitors are capturing that you’re not. Most SEOs run gap analysis once during initial research, then forget about it. That’s backwards thinking.

I run content gap analysis quarterly for every client because search landscapes shift constantly. New competitors emerge, SERP features change, and seasonal trends create fresh opportunities. The workflow I’m sharing here is what I use during a typical client onboarding — it’s repeatable, scales across industries, and finds gaps that actually convert.

Semrush’s Keyword Gap tool makes this process systematic rather than guesswork. You’re not hunting random keywords; you’re reverse-engineering what’s already working for your direct competition. Here’s exactly how I do it.

Step 1: Identify Your Real Competitors (Not Who You Think They Are)

Skip the “competitive landscape” PowerPoint exercise. You need competitors who are actually stealing your organic traffic, not industry leaders you aspire to compete with someday.

In Semrush, go to Domain Overview and enter your domain. Scroll to “Main Organic Competitors” — these are domains that rank for similar keywords, not necessarily similar businesses.

Look for three competitor types:

• Direct business competitors: Same products/services, similar business model
• SERP competitors: Different business but ranking for your target keywords
• Content competitors: Publishers/blogs that dominate informational queries in your space

Pick 3-5 total. More than that creates noise; fewer misses opportunities. I also check their paid competitors tab because PPC keyword selection often reveals high-intent terms they’re not prioritizing organically yet.

Step 2: Run the Keyword Gap Analysis

Navigate to Keyword Gap under Competitive Research. Enter your domain in the first field, then add your 3-5 competitors in the remaining fields. Set your location and device preferences.

The default view shows all keywords, which is useless. Click the “Missing” filter to see keywords where competitors rank but you don’t. This is your gap analysis goldmine.

Don’t get excited about the keyword count yet. Most of these keywords are irrelevant, too competitive, or have zero search volume. The filtering is where the real work happens.

Step 3: Filter for Realistic Opportunities

Apply these filters in order:

Search Volume: Set minimum to 100 monthly searches. Lower volume keywords might be relevant for specific niches, but you’re looking for systematic gaps with scale potential.

Keyword Difficulty: Set maximum to 50 unless you have serious domain authority. Most SMBs should stick to KD under 30 for consistent wins.

Intent: Filter for Commercial and Informational intent. Navigational queries are usually branded searches you can’t compete for. Transactional terms are valuable but often highly competitive.

Position Range: Look at competitor positions 1-20. If they’re ranking beyond page 2, it’s not a proven opportunity.

After filtering, export the results. You should have 50-200 keywords depending on your niche size.

Step 4: Cluster Keywords by Topic

Raw keyword lists don’t translate to content strategy. Group related keywords into topic clusters that could be covered by single pieces of content.

I do this manually in Google Sheets with columns for:

• Keyword
• Search Volume
• Keyword Difficulty
• Topic Cluster
• Content Type (blog post, product page, tool page, etc.)
• Priority Score (calculated later)

Look for semantic relationships, not just exact keyword matching. “Best project management software,” “project management tools comparison,” and “project management software reviews” all belong in the same cluster.

Step 5: Map to Existing Content vs New Content

This is where many gap analyses fail. You find opportunities but don’t connect them to actionable content decisions.

For each topic cluster, determine:

• Existing content to optimize: You have content that could rank for these keywords with updates
• New content needed: No existing content covers this topic adequately
• Content format gaps: You have blog posts but competitors are winning with tools, calculators, or comparison pages

Step 6: Prioritize by Traffic Value × Effort

Create a priority score using this formula: (Search Volume × Average CPC) ÷ Keyword Difficulty. This weights commercial intent and realistic competition level.

High-volume informational keywords with zero commercial value rank lower than medium-volume commercial keywords you can realistically target.

Alternative Tools: Ahrefs and Mangools Approaches

Ahrefs Content Gap tool works similarly but with better filtering options. The “Also rank for” feature shows keywords where you rank poorly (positions 11-100) versus not at all, which reveals optimization opportunities alongside gap opportunities.

Ahrefs also provides more granular SERP feature data, so you can avoid targeting keywords dominated by featured snippets, images, or local packs unless that matches your content strategy.

Mangools doesn’t have a dedicated gap analysis tool, but you can approximate the workflow:

1. Use SERPChecker to analyze competitor rankings for your target keywords
2. Export their ranking keywords from SERPWatcher
3. Cross-reference against your own keyword tracking to identify gaps manually

It’s more manual but works fine for smaller keyword sets or budget-conscious operations.

Why Quarterly Gap Analysis Beats Project-Based

Search results change constantly. New competitors enter your space, existing ones publish new content, and Google updates algorithms. A gap analysis from six months ago misses current opportunities and wastes time on outdated insights.

I’ve seen 40% keyword overlap changes in competitive niches within a single quarter.

Run this analysis every 90 days, not just during strategy phases. Set calendar reminders and treat it like any other recurring SEO maintenance task.

Verdict

FAQ

How often should I run content gap analysis?

Every quarter. Search landscapes shift too quickly for annual analysis to remain actionable. Set up recurring calendar reminders and treat it as ongoing competitive intelligence, not a one-time research project.

Should I target every keyword gap I find?

No. Most gaps exist because the keywords are too competitive, too low volume, or outside your business focus. Use the prioritization framework to focus on gaps that align with business goals and realistic ranking potential.

What if my competitors are much larger domains?

Filter more aggressively by keyword difficulty (KD under 30) and focus on long-tail opportunities. Large domains often ignore lower-volume keywords that could be perfect for smaller sites. Also analyze their newest content — they might be testing less competitive topics.

Can I do gap analysis for local SEO?

Yes, but modify the approach. Use location-specific competitors (businesses ranking in your geographic area) and focus on local intent keywords. Tools like BrightLocal or Whitespark complement Semrush for local gap analysis by showing Google Business Profile optimization opportunities.