And why does it matter?
Instagram says 3-5 hashtags are the sweet spot, but I like using 3-11 as long as they are all relevant.
That's the keyword: RELEVANT
Refer to the graphic for my suggestions on how to get to 11 hashtags, but if you can think of just 5 that accurately identify the content, stick with 5.
Keep it simple.
Change it up if you see your hashtags are not getting more eyes on your content.
In other words, test, test, and test again.
One final word.
On LinkedIn, only use 5 and if you put them at the end of the post, each one gets its own line.
On Facebook, use 2-5. More than that will get you fewer eyes on your content.
Trust me here. Using more not only looks spammy but also results in fewer impressions.