It is common to find many overlaps between both platforms – from users to the same advertising system. However, there are several differences too. For example, the demographics and the nitty-gritty specifics of interactions vary. Facebook does have more monthly users compared to Instagram – 2.7 billion compared to about 1 billion for the latter. This will inevitably affect the reach of your ads. But about 70% of Instagram users are said to be under 35 years old. Therefore, based on the demographics and your target audience, you can either use both or one of the platforms to advertise a product or service.
There are a few other differences between Instagram and Facebook ads that you should be aware of. During multiple A/B testings between the two platforms it became clear that the cost per click (CPC) is slightly more for Instagram than Instagram, however the same test showed that Instagram had a 1.44% click through rate (CTR) where Facebook had a 0.90% CTR.