Also, Instagram simply doesn't show your stuff to 100% of your followers 100% of the time, so it's just impossible.
If you were to ask, could an 800K account with 150.000 likes per post charge as much as an 1.5MM account with 150.000 likes per post? Yes, and it would make sense. It's just rare that someone has an higher than 10% ratio. I've seen them upwards of 20% with the current algo.
As I said, as an advertiser you should look to pay about $2K per 1MM impressions (which are about 50k likes). In other words, if you paid $2K to get your product posted on an account with the audience I described previously and it gets 50K likes, you're doing it right and you're supposed to make a profit.
$2K per 1MM impressions it's my opinion tho (and it's pretty market average in my experience). It's derived from the fact that you can pay $3.5K to FB directly to get 1MM female US impressions on IG - with zero hassles and better traceability.
Is it 10% for any one post?
My question is, in a rolling 30 day period, are 10% of all followers overall liking posts, or any given random 10%?
is there a standard metric to check how many of your followers are active?
if you have 1.5mm followers, but the same 10% on average are the ones to engage/like your posts, is it the same as having 15,000 really engaged followers?