SimilarWeb vs Google Analytics Traffic Data Mismatch, Explained

Since Alexa Website Ranking system is no longer relevant or has become passe, many bloggers, webmasters, publishers, and online advertisers are now turning to SimilarWeb as their primary means of measuring their or another website's traffic and importance in the context of both local and global internet landscape.

I think it was around October 2017 when I started monitoring's data on SimilarWeb. It was after I learned that two of my banner advertisers have started taking a look at my blogsite's data on that market intelligence website in determining my exact clout and reach.

SimilarWeb vs Google Analytics

Earlier this year, I noticed that my SimilarWeb traffic data seemed to always be way below that of my Google Analytics figures. It worried me a bit -- but I let it pass, hoping that the numbers would match sooner rather than later. "Maybe they're just having problems crawling my site. I'll give it two more months before making them aware of this issue," I thought.

But lo and behold! Fast forward to May 2018 data,'s SimilarWeb numbers are still way lower than what it gets on Google Analytics. This time, I didn't let it pass. On June 11, 2018, I sent SimilarWeb Support Team this email:



Hi SimilarWeb!

I've been referred to this support email account by your Twitter page. :-)

I've been meaning to ask why SimilarWeb numbers of are always lower than my actual Google Analytics numbers? Where does SimilarWeb get its data and how does it make sure that all websites are being treated fairly in terms of ranking? My SimilarWeb numbers also affect the way my advertisers value my website so it matters to me.

Thank in advance!

Mark of

Two days later - June 13, 2018, Mr. Greg Schrank of SimilarWeb Help Center replied to my email with this explanation:



Hi Mark,

We collect our data, in part, through our diverse worldwide panel comprised of hundreds of millions of user devices which use one of our thousands of free apps or add-ons in exchange for access to their anonymous mobile app and website usage data. Once a user downloads one of our free products they join a global panel that helps us understand the digital world. We then run this data through complex statistical algorithms and incorporate those estimations into our platform.

It is impossible to be 100% accurate. The “source of truth” varies by company. In some companies Google Analytics is the truth, and in others it can be another analytics provider. Direct Measurement tools tend to have a discrepancy of up to 20% between each other, while SimilarWeb has a margin of error due to its projection methodology. Many of our customers find that we are within 10-20% of their numbers. Though really, the value is in the features and trends - not in the numbers. We believe when looking at SimilarWeb, it is invaluable to see if the trends make sense for your business’s ecosystem.

We invite site owners to connect their Google Analytics account to our platform to provide users with multiple data sets. In order to connect:

1. In the footer of, click the ‘Publicly connect Google Analytics’ button
2. Click on – ‘Connect with your Google Analytics account’
3. Select the Google Analytics Account, Property and View for the website you’d like to connect

For more information on our data methodology, please refer to the following page:


Greg Schrank
Customer Care Specialist
SimilarWeb Global Customer Care

I thought Greg's explanation is pretty spot on or direct to the point.

Frankly, it doused my worries and made me believe in SimilarWeb more. I felt their company's desire to do this well.

However, I hope they are also continuously doing the best they can to make their figures more accurate or closer to actual numbers just to make their rankings more truthful and reliable -- since, as I've noted above, it has business repercussions for website owners like me.

If you're a blogger or webmaster who also has the same issue with SimilarWeb, let me know if you found this entry useful and informative. Also, kindly leave a comment below if you have a valuable input that you want to add to the discussion. If you wish so, you may also send me a message on Facebook, Twitter, or Instagram. Cheers!

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