They're the same thing, it's just that one of them is an excess. The only difference is in amount.

I personally draw the line at where confidence ceases to reflect reality and the person's real ability.

Arrogance is defined by Merriam-Webster as,

"1 : exaggerating or disposed to exaggerate one's own worth or importance often by an overbearing manner "

Confidence is defined by Merriam-Webster as,

"2 : the quality or state of being certain : certitude "

Arrogance is basically a false pride, while confidence is just pride.

Arrogance is walking into a room thinking you're better than everyone. Confidence is walking into a room and not having to compare yourself to anyone else in the first place.

:)

Arrogance is a type of confidence. And as much as i hate to alleviate people's insecurities, i shall do so this once. Get a grip!

Arrogance is when a person is so lacking in confidence that they feel the need to constantly remind everyone else how "confident" they are =p

Arrogance is confidence displayed in a negative or egotistical way.

Confidence is when you go into battle, knowing your going to die. Arrogance, is when you go into battle, thinking your going to win when greatly outmatched, then being killed.

Confidence is an inward projection of security. If asked, one can say, "Yes I think I will do well on this test" if you honestly believe you will.

Arrogance is an outward projection of confidence with and inward projection of insecurity. People can sense that inward projection most often because of subtle nuances in interaction. Often it could express itself outwardly if one says, "Yes I think I will do well on this test" if you honestly believe you will, although no one asked.

Confidence involves more modesty.

Arrogance is more rude, even in defeat, while confidence stays humble, especially in defeat.

When someone can control his arrogance, then he will gain confidence.