SEMRush vs Google Search Console: How accurate is SEMRush organic data?

We love SEMRush at Varn. It’s a useful tool that helps us go deep on SEO analysis giving access to keyword data, competitor insights, backlinks and much much more. However it has its limitations, and as is often the case with third-party tools, a lack of access to direct analytics in the form of Google Search Console or GA4 can lead to a lack of accurate data.

With the above in mind, we were curious about the accuracy of SEMRush when it comes to the ability to track organic traffic for our clients, so by analysing 32 of our clients Google Search Console profiles, we were able to compare with the results visible in SEMRush and the findings were interesting.

SEMRush both over and underestimated the traffic

SEMRush was only within 10% accuracy when compared to the GSC data twice and they were both on data-sets of around 1,500 visits from organic search per month.

The caveat for this data is that SEMrush likely encompasses all organic traffic, whereas Google Search Console (GSC) data is limited to Google traffic. However, due to the disruption in GA4 data caused by consent mode in 2024, we have opted for GSC data. Despite its narrower scope, GSC still offers a statistically relevant basis for comparison.

When looking at the dataset, 15 websites were overestimated on their traffic and 15 websites underestimated. The traffic was overestimated by an average of 152% across the 15 websites analysed and underestimated by 51%. So when SEMRush overestimates, it tends to be much less accurate than when it underestimates.

Box: This represents the middle 50% of the data (interquartile range), showing the main spread of traffic estimation differences.

Median (Orange Line): The line inside the box represents the 50th percentile (median), showing the central tendency. For overestimates, it’s above 100%, and for underestimates, it’s near 0%.

Whiskers: These extend from the box to show the range of the data, excluding outliers. For overestimates, the whiskers range from near 0% to over 300%, while for underestimates, they range from about -100% to near 0%.

Outliers: Any data points outside the whiskers (though none are present in this chart) would represent extreme values.

SEMRush overestimated websites with high organic traffic

For websites with higher organic traffic levels, SEMRush tended to overestimate their performance vs Google Search Console on organic search. Even accounting for the marginal increase in data that SEMRush will have from other organic search engine estimates, the discrepancy between the two is very large (an overestimation of 107% of websites with 10,000 organic traffic/clicks a month on average.

What does this mean for search marketers?

When it comes to tools providing competitive intelligence they are great for content planning, proposal documents and benchmarking for results that account for market changes. However, for obvious reasons they are not as accurate as client specific data sets and can be very inaccurate at times.

When you are comparing data, make sure that you keep it all on the same platform. So if you are looking at SEMRush data vs the competition, then do not be tempted to include your data from Google Search Console (even though this is in theory more accurate). Instead, keep all the data sources consistent and have a caveat that whilst the total figures may be inaccurate, the percentages in relation to the other websites is the more useful statistic. Additionally when looking at historical traffic in SEMRush, be cautious of how this compares to your Google Analytics/Search Console as this too can show differing traffic fluctuations.

Key takeaways

Average Overestimation: In cases where SEMrush overestimates traffic, the average overestimation is 152.26%.
Average Underestimation: In cases where SEMrush underestimates traffic, the average underestimation is -52.84%.
SEMrush’s estimates deviate from GSC data by either significantly overestimating or underestimating, with an overall tendency toward overestimation when it occurs.
SEMrush overestimated traffic compared to GSC in 15 cases and underestimated in 15 cases.