The maths for a bluff is:

bet/(bet+pot)

So if I make a pot size bluff it's 1/(1+1) = 1/2 = 50%

So I will need my opponent to fold 50% to make a pot size bluff profitable.

But how do you actually use this while playing??

I thought it would be about bluffing on boards that don't connect with lots of hands.

So I make a potsize bluff on K72r because I can expect villian to fold 50% of their range.

But on a board like J 10 9 I'd expect villian to be calling most of his range, so in this spot I need to bluff with a small size.

However when I watch good players video's they seem to be doing the opposite and bluffing small on the dry boards K 7 2r boards