Spanish has two common verbs – conocer and saber – that usually mean “to know”, in English.
1. General rule for conocer
In general, conocer means “to know of” or “to be familiar with” a thing or a famous person.
Note: when conocer is used in this sense, i.e. “to know of”, or “to be familiar with”, it is always used in the present tense.
¿Conocés el bife de Argentina? Sí, lo conozco.
(Do you know of Argentinian beef, i.e. are you familiar with it? Yes, I know of it, i.e. I am familiar with Argentinian beef.)
Note that “el bife” is used in the example. A definite or indefinite article is required when conocer is used with a food or drink.
¿Conocés el Don Quijote? No, no lo conozco.
(Do you know of Don Quijote, i.e. are you familiar with the book, Don Quijote? No, I do not know of it, i.e. I am not familiar with it.)
Conozco un libro bueno.
(I know a good book.)
¿Conocés la película, Blade Runner? Sí, la conozco.
Do you know of the movie, Blade Runner, i.e. are you familiar with the movie? Yes, I know of it, i.e. I am familiar with it.
Conozco a Rolling Stones.
(I know of the Rolling Stones, i.e. I am familiar with the band.)
Conozco a Oprah.
(I know of Oprah, i.e. I know who she is.)
Conozco a Oprah personalmente.
(I know Oprah personally.)
In this case, the statement makes clear that the speaker isn’t just familiar with Oprah, the speaker actually knows Oprah personally.
2. Limitation on general rule for conocer
Conocer is used, as provided in 1 above, when the object is qualified by a specific name, location, brand, title, or some other limitation that makes the object specific. Otherwise, if the object is general, saber is used instead of conocer.
Conozco la película, Blade Runner.
(I know of Blade Runner, the movie, i.e. I am familiar with it.)
Sé qué es una película.
(I know what a movie is.)
Note, in this case, saber is used, not conocer, because a film is referred to, but not a specific film.
Conozco el bife de Argentina.
I know of Argentinian beef, i.e. I am familiar with it.
Sé qué es el bife.
(I know what beef is.)
Note, in this case, saber is used because beef is referred to in general and is not qualified or described more particularly in any way.
Sé qué es un coche.
(I know what a car is.) Again, the usage is so broad and not specific, so saber is used, not conocer.
3. Exceptions to the general rule for conocer: places and regular (non-famous) persons.
a. Conocer and places.
When conocer is used to describe a place, it does not just mean that someone is familiar with such place. Instead, it means that someone has visited the place. In this context, conocer is a synonym for visitar.
¿Conocés la ciudad de Nueva York? Sí, la conozco.
(Have you visited New York? Yes, I have visited it.)
In the above example, conocer is used in the present tense but refers to the past.
¿Conociste la ciudad de Nueva York? Sí, la conocí.
(Did you visit New York for the first time? Yes, I visited it for the first time.)
Note: when conocer is used in the pretérito indefinido, it means “visited” for the first time.
Voy a conocer Nueva York en Diciembre. Conoceré Nueva York en Diciembre.
(I am going to visit New York in December. I will visit New York in December.)
In these examples, conocer is used in the present tense and in the future tense, but in both cases refers to a future action.
¿Has visitado Nueva York? Sí, la he visitado.
(Have you visited New York? Yes, I have visited it.)
This example illustrates how visitar may be used instead of conocer.
b. Conocer and regular (non-famous) persons.
Note that the general rule, in 1 above, applies when conocer is used to describe a famous person.
However, when conocer is used to describe a regular person, it does not just mean that someone knows of another person, i.e. is familiar with such other person. Instead, it means that someone has personal knowledge of the other person, e.g. through a personal meeting or by communication such as by letter, e-mail, or telephone.
¿Conociste a Juan? Sí, conocí a Juan en la fiesta ayer.
(Did you meet Juan? Yes, I met Juan at the party yesterday.)
¿Has conocido a Juan? No, pero lo voy a conocer en la fiesta mañana.
(Have you met Juan? No, but I am going to meet him at the party tomorrow.)
¿Conociste a María? Sí, la conocí porque me llamó y hablamos la semana pasada.
(Did you meet María? Yes, I know her personally because she called me and we spoke last week.)
However, if someone only knows of a regular person, i.e. does not have personal knowledge of such regular person, then saber is used instead of conocer.
Sé quién es Juan.
(I know who Juan is.)
In this example, the speaker knows who Juan is but has no personal knowledge of Juan.
4. Saber – the two general uses for saber
In general, saber has two uses.
In one use, saber means “to know” information about someone or something. In the other use, saber means “to know” how to do something well, i.e. to have a skill.
a. Saber: to know information about something or someone
Yo sé que los Estados Unidos están al norte de México.
(I know that the United States is to the north of Mexico.)
Sé que Buenos Aires es la ciudad más grande de Argentina.
(I know that Buenos Aires is the biggest city in Argentina.)
Sé que ella nació en 1970.
(I know that she was born in 1970.)
b. Saber: to know how to do something well, i.e. to have a skill.
¿Sabés cocinar? (Do you cook well?) Sí, sé cocinar. (Yes, I cook well, i.e. I am a good cook.)
¿Qué sabés hacer?
(What do you know how to do, i.e. what skills do you have for this job?) Note: this is a standard job interview question.
No sé hacer nada. (I do nothing well.)
¿Sabés manejar Excel?
(Are you skilled in using Excel?) Note: here, manejar is a synonym for usar.
Sé Excel un poco. (I have some skill with Excel.)