¿Qué hora es? - What time is it?
Es la una. - It's one o'clock.
Son las dos. - It's two o'clock.
Son las doce. - It's twelve o'clock.
Note: The plural form (son) is used for two o'clock through twelve.
Instead of saying 15 minutes, cuarto is generally used. Media is used instead of 30 minutes.
Es la una y cuarto.
It is one-fifteen (1:15).
A la una y media.
At one-thirty (1:30).
Note: Minutes up to half an hour are added to the hour using y; above that, they are typically subtracted from the hour with menos.
Son las cinco y diez.
It's ten after five.
Son las tres menos cuarto.
It's two forty-five (2:45).
Son las tres menos diez.
It's ten till three (2:50).
