Is there any way to count it?

I found a formula on the Internet:
The process starts with the pot odds that he is getting. Hero would need to call $6 to play for a pot of $12 (CO’s $8 raise + the dead blinds $3 + Hero’s $6 call – $5 rake):

Pot Odds = $6 / $12 = 0.5 = 50% raw equity needed
This formula assumes that we always get in postflop our stacks. (probably)

Following this formula, I should only call this range: Villain's or is 13%.

Thanks!