How Accurate is Google Keyword Planner? An In-Depth Analysis

When it comes to keyword research, do you trust Google Keyword Planner blindly? A recent study reveals that this commonly used tool might not be as accurate as many marketers believe.

Unpacking Google Keyword Data Sources

In the world of SEO, having the right tools at your disposal can make or break your strategy. Google provides two primary sources for keyword data: Google Search Console and Google Keyword Planner. Search Console is typically regarded as the most reliable source for tracking impressions, clicks, and keyword rankings. However, you can only view this data if you already rank for a given keyword. That limitation leads many marketers to turn toward Keyword Planner for fresh insights into search volumes and keyword research, even though it groups similar terms and rounds figures into broad buckets.

Our Study of Over 72,000 Keywords

To put google’s keyword planner to the test, we ran a comprehensive analysis of 72,635 random keywords with estimated monthly search volumes between 1,000 and 10,000. We ensured that each page in our sample ranked in the top 10 results for its target keyword during June 2021, making Search Console impression data a valid proxy for actual search demand. By comparing Search Console impressions with Keyword Planner estimates for the same month, we could quantify the tool’s accuracy and identify patterns of overestimation and underestimation.

The Numbers Behind Overestimation

We found that 91% of the time, Keyword Planner search volumes were overestimations compared to Search Console impressions. To categorize these discrepancies, we set a threshold of ±50% deviation: estimates within that range were deemed “roughly accurate,” while those beyond it were considered drastic over- or under-estimations. Our breakdown showed that Keyword Planner’s search volumes were drastically overestimated 54% of the time, roughly accurate 45%, and drastically underestimated just 0.5% of the time. Notably, 14.8% of keywords were overestimated by at least four times their actual impressions.

The Main Reason for Overestimations

The primary culprit behind search volume overestimation is keyword grouping. Keyword Planner aggregates keywords it deems “similar,” sometimes lumping together misspellings, brand names, and informational queries. For instance, the keyword “ahrefs” registered 25,859 impressions in Search Console for June 2021 but showed 33,100 in Keyword Planner. While minor misspellings might not skew intent drastically, other groupings can. Keywords like “bank of america,” “american banks,” and “banks in america” share a grouping in Keyword Planner, yet user intent varies significantly—from finding a major bank’s site to researching a list of institutions. This mechanism can inflate search volumes and lead to misplaced emphasis in keyword research.

Overestimations of Over 400%

Some queries exhibited extreme overestimation, with suggested search volumes exceeding actual impressions by more than 400%. These tended to be local-intent keywords where true demand is geographically concentrated. For example, the query “golf courses” returned markedly different SERPs when tested from Nashville, Los Angeles, and Chicago, with very few overlapping domains. Since Keyword Planner reports nationwide volumes, location-specific demand gets lost. A small local business might see great national search volume on paper but only a fraction of that traffic in its immediate market, leading to unrealistic SEO expectations.

Ahrefs Versus Google Keyword Planner

We also compared these results against a third-party tool, Ahrefs, which ungroups keywords to report distinct search volumes. Our data showed that Ahrefs underestimated search volumes in only 1.84% of cases, compared to Keyword Planner’s 0.5% underestimation. Ahrefs was “roughly accurate” 60.68% of the time, significantly higher than Keyword Planner’s 45.22%. Moreover, Ahrefs’ drastic overestimation rate was just 37.48%, compared to 54.28% for Keyword Planner. These figures highlight the benefits of using multiple data sources and tools that refine google’s raw numbers.

“Search volume shouldn’t be the sole factor guiding your content calendar. Traffic potential provides a clearer picture of the real traffic you can earn.” — SEO Analysis

What This Means for Your Strategy

Going forward, treat Keyword Planner as one data point in your keyword research toolkit rather than gospel. Use it to brainstorm topics and gauge general trends, but always cross-reference search volumes with Search Console data and tools like Ahrefs. Focus on traffic potential over raw search volumes to set realistic expectations for organic performance. Diversifying your approach will prevent costly overreliance on any single source and ensure you target keywords that truly drive traffic and conversions.

• Actionable takeaway: Combine Google Keyword Planner estimates with Search Console insights and a tool like Ahrefs to identify keywords with high traffic potential and realistic search volumes for your target market.