Why The Current Facebook Engagement Rate Calculation Is Inaccurate

Stephane Allard
Co-founder & CEO at Wisemetrics - Stephane is a serial entrepreneur who has been launching internet-related companies since 2001, after a fruitful experience at IBM as web marketing manager. His latest venture was a pioneering social media agency, sold in 2006, which advised Fortune 100 companies.

Update : Facebook has finally introduced an official Engagement Rate in their new Insights. Good news, it’s the same formula that we use in our analytics solution.
Check if your solution still uses a flawed formula! 😉


As the social media analytics field is pretty new, it’s really important to understand how the metrics are computed.

Let’s take for example, one of the main metrics in measuring one’s page performance : the “Engagement Rate”.

What is supposed to be measured with the Engagement Rate ? “The Engagement Rate measures how well your Fans interact with your content”. That’s a common definition.

What’s that supposed to mean? If you have a 0.02% Engagement Rate, it means 0.02% of your fans have engaged with your content, isn’t it?

Only the formula commonly used does not measure that. Not at all. 

Facebook Engagement Rate Formula

Another commonly used formula is this one :

First Problem with these formulas : they don’t include all interactions

Don’t you think, there’s something missing?

What about the interactions when your fans play your videos, look at your photos or click on your links? Aren’t these actions a BIG part of your engagement? For some Brands or Pages (fashion, beauty, e-commerce or even cars manufacturers for example), we may even argue that these interactions are close to be the most valuable ones.

But in the commonly used formulas, these interactions are nowhere to be found! For some Pages, it may represent close to 80% or more of the total interactions, and they’re not included in the calculation! The Engagement Rate is supposed to measure how well your fans respond to your content, but a big part of their response is not measured.

What kind of insights do you get with that? No wonder the average engagement rate is below 0.2%.

Second Problem : they are based on the number of fans only

Brands need to focus on the number of people reached, not the number of fans!
Facebook’s great promise is in viral marketing (touching friends of fans), not in the number of fans you have. Especially when you know that close to 84% of your Facebook Fans don’t ever see your content


Let’s compare two Pages.

Facebook Engagement Rate Measurement

Which one is the most successful on Facebook ?

The second one for sure : close to two more times fans, a bigger engagement rate.


Well. We’re not so sure about this. Let’s insert another metric.

Facebook Engagement Rate with Users Reached


If you’re measuring your engagement rate based on the number of fans, you may be hiding the hard truth : what counts is not the number of fans, but the number of users reached (who cares if they’re fans or friends of fans anyway?).

A visibly smaller page with less overall interactions but with more shares and/or with fans with a wider friends network may well outperform another page with way more fans or more interactions, when it comes to number of users reached.

So, to help you measure how well your content engage your readers, these formulas include all your fans, even if more than 80% of them simply can’t engage with your content (if they don’t see it how could they like it, comment it or share it ?) and, icing on the cake, it’s not including the users who are not fans but are able to interact with your content because they see it in their newsfeed?


Third problem : they mix fans data with fans AND non-fans data

It’s a bit like comparing apples and pears. The formulas make a ratio out of interactions (done by fans and non-fans alike) with the total number of fans only. This creates a bias towards a bigger engagement rate. To be accurate, the formula would need to exclude all likes, comments and shares from non-fans.


Fourth problem : they favor Pages with high publishing rates

Want to trick your Engagement Rate further? Follow this advice : post more. It’s quite simple and it works.

Engagement Rate and Number of posts

1. You’ll reach more fans, it means that more of them will have the opportunity to interact with your content, thus increasing your interactions count
2. Every user reached (fans or not) will have more opportunities to like, comment or share your content (a post can only be liked or shared once!). This will increase your interactions count as well.

These formulas clearly favor Pages with high publishing activities, even if, on average, their posts perform less than posts on other Pages with lower publishing activity levels.

Fifth problem : they don’t measure users but interactions

We want to know the proportion of our fans that interact with our content, but we’re not measuring unique users, we’re measuring the number of interactions. One single fan may be responsible for 28 likes, 13 comments and 6 shares. In the formulas above, this will be considered as 47 “users”…

All in all…

These are inappropriate formulas to get unbiased insights on whether your community on Facebook enjoys your content or not.

What remains is a ridiculously low Engagement Rate that makes your boss wonder if Facebook works at all.

The formulas may still be useful, nonetheless, for benchmarking purpose for example, even if it they are biased. But, in our opinion,they should be called Activation Rate, or something similar, not Engagement Rate. They certainly do not help you evaluate if your community enjoys your content.

How to measure your true engagement rate

Based on our previous comments, we’ve devised the following formula :Engagement rate


And if you’re doing an Engagement Rate benchmark between several Pages, we advise you to use the following formula :

Engagement Rate formula

The formulas present the following benefits which makes it a lot more accurate :

– It includes all type of interactions : photo views, video plays, link clicks, quotes… Not only likes, comments and shares.
– It compares fans and non-fans engagement (Users engaged may or may be not fans) with total number of fans and non-fans reached
– Only people who had the opportunity to see your content (thus the opportunity to interact with it) are included
– The impact of publishing rate is isolated (for the second one)

On top of that, this is probably the way Facebook itself would measure Engagement. Have you seen how “Virality rate” is measured by Facebook ? It’s the number of people creating stories/Number of People reached. Not the number of shares/number of fans.

And at the end, it really answers the question “Does my content engage my community or not ?”

Using the first formula you may expect Engagement Rates of 30,40, 50% or more.

Now the boss is happy.

EDIT : Added the fifth problem on the 4th of July

EDIT : Added the Engagement Rate formula for single Pages, thanks to our readers comments, on the 24th of September

EDIT : Added the Engagement Rate formula based on PTAT, on 11th of October

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