The most common Korean word for “birthday” is 생일 (saengil). There is one more word with a similar meaning — compare them below. 「birthday」는 한국어로 생일.
birthday
TOPIK 1 · noun
Words and levels: TOPIK I essentials (National Institute of Korean Language standard curriculum, KOGL Type 1) · examples: Cheesepotato
치즈감자