First, a person would likely ask you "¿Cuándo es tu cumpleaños?" to ask "When is your birthday?" To that, you would respond "Mi cumpleaños es..." and then the date. You use the singular verb "es" because birthday is a singular day (even though the word here looks plural).
Por ejemplo:
¿Cuándo es tu cumpleaños?
Mi cumpleaños es el treinta de marzo.
"Cumpleanos" means "birthday" in Spanish.
Birthday in Spanish is "cumpleaños" (singular or plural noun). Happy Birthday! = ¡Feliz cumpleaños!
"when is my birthday" translates to "cuando es mi cumpleaños" in Spanish.
Cumpleaños.
Cumpleaños
"Mi cumpleaños". That is how you say "my birthday".
Mi cumpleaños es (your birthday)
it's his birthday - "es su cumpleanos"
Cuando(when) es(its) tu(your) cumpleaños(birthday).
cumpleanos
cumpleanos
regalos