Prepositions por & para (simplified)

Meaning

Por and para are a little confusing because they both can be translated as for. But they have different uses. Here are some basic ones:

Para

We use it for purpose / destination / goal:

La falda es para María. (The skirt is for María.)

Tengo un presente para Pedro. (I have a present for Pedro.) 

Voy a la escuela para aprender. (I go to school in order to learn. In this case it means in order to.)

Por

We use it for duration of time intervals:

Estoy en Nueva York por siete días. (I am in New York for seven days.)

Or for exchange:

Compro un vestido por veinte euros. (I buy a dress for twenty euros.)
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