This SEO tool comparison pops up more than any other: SpyFu vs Semrush vs Ahrefs. These past few years, we've seen battles for the strongest tool to deliver keyword insights, making this latest shift that I'm about to show you, an actual game-changer.

After Years of Competition, A Surprising Twist

SpyFu has more keyword data than Semrush and Ahrefs in search after search, and I will prove it. A colleague first mentioned this to me after using all three tools for their own keyword research. I had to test it for myself.

I compared random domains to see which tool gave us deeper keyword data across different industries and even website sizes. Here's what I found from my experimentation:  

A Deeper Look at Keyword Data

Let’s dig into some numbers. SpyFu consistently provides broader keyword coverage compared to Semrush and Ahrefs, and I can back that up:

  • Best Buy: SpyFu tracks 10 million keywords, compared to Ahrefs’ 4.3 million and Semrush’s 6.76 million—a clear advantage for SpyFu with at least 50% more data.
  • Home Depot: SpyFu tracks 21 million keywords. Ahrefs shows 8.7 million, and Semrush comes close with 19.4 million. 
  • A Place for Mom: SpyFu identifies 1 million keywords, while Ahrefs offers 366,000 and Semrush 676,000. 

With that last one, I wanted to measure a mid-size domain in case we were overserving ecommerce giants. Again, SpyFu holds a significant lead.

SpyFu didn't always have this advantage. It's a qualification that we used to concede to the other tools whenever someone asked about a comparison. I knew that they had a bigger reach in the past, so I assumed that was the case for a while. Knowing it was one of our weaknesses, I decided to change what I could.

We started expanding SpyFu's reach. We added more countries to our data. We added more keywords. That careful focus helped us grow SpyFu to be a rich resource for SEOs and PPCs competing in US and international markets.

And just to clarify, these counts don't roll those countries together. Comparisons are done mostly on US data to US data, but I did test head-to-head with other countries' data too.

We opened the 3 tools and compared domain after domain

International Insights

Here's where I had my biggest surprise of the day. SpyFu’s strength in international markets has been growing, but I had no idea that we'd eclipse these companies that had reputations for global reach in SEO keywords. SpyFu outperformed Semrush and Ahrefs in regions that they had traditionally dominated in the past:

  • Grain.com in the UK: SpyFu tracked 1065 keywords compared to 823 for Ahrefs and 633 for Semrush.
  • Grain.com in Germany: Switching countries, SpyFu captures 315 keywords to Ahrefs' 237 and Semrush with 200 for this domain.
  • HubSpot in Singapore: SpyFu captured 43,341 keywords, far surpassing Ahrefs 22,100 and Semrush's 25,300.

Granted, this is a small sample, but I plan to keep the comparisons going. I'm excited--at least from our first stab using relevant, competitive domains with strong international SEO performance--that SpyFu does so well in serving the biggest portion of their keywords.

I didn’t expect us to be beating these international companies—especially not on their own home turn. Ahrefs is originally a Ukrainian company now based in Singapore, and Semrush started in St. Petersburg, Russia, and is publicly traded on the New York Stock Exchange. These are global players with deeply international roots, and I always assumed that international data would be their strong suit.

"'How are we the best in the world at--the world?"

It turns out that the number tell a different story. We've gone past keeping up; we’re beating them on core metrics. Whether it’s Singapore, Ukraine, or even broader international markets, SpyFu consistently pulls ahead vs Semrush and Ahrefs.

For example, in Singapore, I thought for sure Ahrefs, being based there, would have the edge. I'm not saying I was giving them an advantage, but I wanted to try to erase any bias I might have had with my examples by purposely choosing their original countries. 

You're getting more with SpyFu, and it's not limited to U.S.-centric results.

Why This Really Matters

I'm throwing around some big numbers, so let's stop to talk about where this really matters. It's hard to illustrate the impact of this size difference when we're talking about millions of keywords, but when you're working with a part of your site like a blog or a specific page, you have much smaller numbers. You need every bit of data to help you glean meaningful insights about the page. 

If a page ranks for 1000 keywords, but you can only see 300 of them, you will miss details that could swing your decision about what to do next with that page.

This grows especially important in two levels of research: one, when you are working with small and local businesses. Second, when you are working to optimize individual pages.

If you're an agency, these are your clients. These are their targeted pages that they're trusting you to grow.

Small and Local Businesses Need Stronger Coverage

In a SpyFu vs Semrush vs Ahrefs matchup, SpyFu finds more of the keywords that your site ranks for, giving you a truer picture of what's happening in your industry. For local businesses, that applies to both your own page and the competition around you. 

In SEO, more organic keywords help you find more audiences that your competitors are reaching. This uncovers topics (and subtopics) that you can create new content for, helping to expand your reach and establish authority. In PPC, just a few hundred additional keywords can completely change how you estimate a competitor's spending power on Google Ads. The keywords they buy--and the ads they run on them--reveals key details about the kind of messaging that pulls in more clicks. You should have every opportunity to learn this kind of intel and make the right adjustments in your own campaigns.

Individual Pages

We have been comparing keyword counts across SpyFu, Ahrefs, and Semrush at the domain level. I wanted to see how keyword coverage held steady or changed when we measured what individual pages rank for.

  • We compared keywords for a page on vidIQ’s website: SpyFu reported 2,136 keywords. Ahrefs tracked 1,800, and Semrush only 1,400. 
  • A URL from EP Wealth—a financial advisor site in Phoenix—shows a similar comparison: SpyFu dominates with 298 keywords. Ahrefs and Semrush fell far behind with only 72 and 75 keywords, respectively.

This granularity matters. At the page level, that is a significant difference in gauging authority and details that help you gain ranks. The more precise the data, the better equipped you are to optimize individual pages for search performance.

This gives you a greater shot at making the right moves for a specific page that you're nurturing to grow in impressions, ranks and clicks.

More Keyword Reach Pays Off

In case it needs to be said, this isn't an ego play. More keywords give you a critical advantage. Whether you’re optimizing for local businesses, competing with global brands, or refining individual page strategies, having access to more data provides:

  • Deeper Context: Long tail keywords and lower-volume keywords still give you helpful direction on a page's strengths and opportunity.
  • Better Competitor Analysis: SpyFu’s ability to uncover data that you would have missed gives you an edge in outmaneuvering competitors.
  • Cost Efficiency: With SpyFu, you don’t face the constant upselling and limits you might encounter with Semrush or Ahrefs. It’s truly “all-you-can-eat” SEO data.

Takeaways

  1. SpyFu leads in keyword volume across most domains: Its data coverage consistently surpasses Semrush and Ahrefs, especially in critical comparisons.
  2. Granular insights make a difference: SpyFu’s detailed reporting on individual pages helps uncover actionable opportunities.
  3. Global reach, local strength: Despite its U.S. focus, SpyFu delivers competitive—and often superior—performance internationally.

The SEO tools that you choose shape your strategy. Keyword research is at the core of SEO success, and keyword data is a fundamental part of why you use these tools. When it comes to comprehensive, actionable insights, SpyFu stands out. If you’re looking for a tool that delivers depth without the added cost or limits, it might be time to give SpyFu a closer look.