Quite means fairly but not very. When used before an adjective or adverb that has an intense or absolute meaning (like absurd, fantastic, right, wrong, impossible, etc) it means completely.
Quiet is an adjective and it means not making noise or not saying much.

Quite significa bastante pero no mucho. Cuando se usa antes de un adjetivo o adverbio que tiene un sentido intenso o absoluto (como absurd, fantastic, right, wrong, impossible, etc) significa completamente.
Quiet es un adjetivo y significa que no hace ruido o no habla mucho.