From experience running ads for clients across industries, I see about 1% of targeted Facebook users clicking ads.
If an ad is clicked less than than, I turn it off (typically). Using this as a base, I’ll extrapolate USA clicks data.
Base on the above screenshot from one of my Facebook Ad accounts this morning (Nov 2017), in the USA there is a potential reach of 230,000,000 targetable Facebook users.
If I had a product and was trying to target all of them with a base CTR (Click Through Rate) of 1%, I would see 2.3 Million clicks from this audience.
If I assume an average daily adspend budget of $10,000 you can see that our reach is between 290K and 1.8M daily users. Facebook suggests that 9,500 to 59,000 users will click on the ad per day!
This shows that Facebook is actually assuming a CTR of around 3%. I’d counter that this is a high number, but with optimization and testing very attainable.
Moving to Worldwide targeting:
When I move to worldwide targeting, the potential CTR facebook offers is about 1.9% of the population on Facebook.
Something to keep in mind, is that Facebook rewards ads and content that is aligned with what a user wants to see. Though it may feel like it on occasion, ads on Facebook are usually highly targeted and meaningful for the intended audience.