vs
QUICK ANSWER
"Cuándo" is a form of "cuándo", an adverb which is often translated as "when". "Por qué" is a form of "por qué", a phrase which is often translated as "why". Learn more about the difference between "cuándo" and "por qué" below.
cuándo(
kwahn
-
doh
)An adverb is a word that describes a verb, an adjective, or other adverbs (e.g., to run quickly, very tired).
A masculine noun is used with masculine articles and adjectives (e.g., el hombre guapo, el sol amarillo).
a. when
Nos vamos a casar, pero el cuándo y el dónde aún no lo sé.We are getting married, but I don't know when or where yet.
por qué(
pohr
keh
)A phrase is a group of words commonly used together (e.g., once upon a time).
A masculine noun is used with masculine articles and adjectives (e.g., el hombre guapo, el sol amarillo).