what is the truth about hook sizes

[keakar]

I cant seam to get a straight answer to the question of what is the difference or even if there is a difference in hook sizes from a #1 hook vs a 1/0 hook size

some hooks are described as being #1 or 1/0 hooks then some say a #1 hook is just a #1 hook and they list a 1/0 hook with different part numbers indicating they are not the same thing.

most websites don't show real actual sizes so I cant tell by looking at them what the measurements are for a 1/0 vs a #1 hook

someone told me a 1/0 is a 1/2" gap and they go up 1/4" for every 1/0 size so a 2/0 is 3/4" gap and 4/0 is a 1" gap, but im pretty sure he is completely wrong about that.

all this is very confusing because im looking into buying a jig mold and I really want to understand what the hook descriptions mean before I buy