Happy Birthday in Korean
What is the difference between these four ways of saying Happy Birthday in Korean?
Are these the most common ones?

생일 축하합니다
생일 축하해요
생일 축하해
생신 축하드려요

Thanks!

Question

Happy Birthday in Korean
What is the difference between these four ways of saying Happy Birthday in Korean?
Are these the most common ones?

생일 축하합니다
생일 축하해요	
생일 축하해
생신 축하드려요

Thanks!

Answer

생일 축하합니다, 생일 축하해요 => most common. I recommend 생일 축하합니다.
생일 축하해 => friend, younger than you. 
생신 축하드려요 => elder than you. like grand parent.