Por is one of the most useful and common prepositions in Spanish, but it can also be one of the most confusing to English speakers. That is because it is sometimes translated as "for," as is the preposition para, and they are very seldom interchangeable.
As a beginner, it is probably best to learn the two prepositions separately and to think of por as a preposition that usually indicates cause or motive, rather than simply as a translation for "for." So in the examples of por usage that are given below, a translation (sometimes awkward) using a word or phrase other than "for" is given, in addition to a translation using "for" (where appropriate). By learning how por is used rather than how it is usually translated, you will find it easier to learn in the long run.
Por To Indicate Cause or Reason
In these usages, por can often be translated as "because of."
- ¿Por qué? (Why? Because of what? For what?)
- Trabajo aquí por el dinero. (I work here because of the money. I work here for the money.)
- No podemos salir por la lluvia. (We cannot leave because of the rain. We cannot leave due to the rain.)
- Conseguí el empleo por mi padre. (I got the job because of my father. I got the job through my father.)
- La asistencia en desempleo por causa de desastre es un programa financiado por el gobierno federal. (Disaster unemployment insurance is a program financed by the federal government. Unemployment insurance for disasters is a program financed by the federal government.)
Por as an Indication of Support
Por is often used this in discussion of political races and issues.
- Voto por Julia Gonzáles. (I am voting for Julia Gonzales. I am voting in support of Julia Gonzales.)
- Es socio de Médicos Por Justicia. (He is a member of Doctors for Justice. He is a member of Doctors Supporting Justice.)
- Mi padre está por no violencia. (My father is for nonviolence. My father is a supporter of nonviolence.)
- Es el representante por el estado de Nueva York. (He's the representative for the state of New York. He's the representative on behalf of the state of New York.)
Por To Indicate an Exchange
One common use of this type is telling how much something cost.
- Compré el coche por $10.000 dólares.(I bought the car for $10,000. I bought the car in exchange for $10,000.)
- Gracias por la comida. (Thanks for the meal.)
- Quisiera cambiar la camisa por una nueva. (I'd like to exchange the shirt for a new one.)
- Hago cualquiera cosa por una sonrisa. (I do anything for a smile.)
Por To Indicate Placement
In such uses, por doesn't indicate a destination, but rather proximity or location. It is often translated as "by" or "through."
- Pasaremos por San Francisco. (We will pass through San Francisco.)
- La escuela no está por aquí. (The school isn't near here.)
- Caminar por la montaña es una actividad de alto desgaste. Hiking through the mountains is a high-fatigue activity.)
Por Meaning 'Per'
Por is a cognate of the English "per" In informal contexts, a English translation of "for" is common.
- El tres por ciento tiene dos coches. (Three percent have two cars.)
- Compré dos regalos por persona. (I bought two gifts per person. I bought two gifts for each person.)
- Trabajo 40 horas por semana. (I work 40 hours per week. I work 40 hours a week.)
Por Meaning 'By'
Por is usually translated as "by" when it points to someone performing an action. Common uses are indicating the author of a book or other work, or indicating the performer of a passive verb.
- Fue escrito por William Shakespeare. (It was written by William Shakespeare.)
- Los tacos fueron comidos por los estudiantes. (The tacos were eaten by the students.)
- Prefiero el libro por Isaac Asimov. (I prefer the book by Isaac Asimov.)
- Puedo leer por mí mismo. (I can read all by myself.)
Por in Set Phrases
Many fixed phrases using por are commonly used as adverbs. The meaning of such phrases isn't always obvious by translating the words individually.
- por causa de (because of)
- por cierto (by the way)
- por el contrario (on the contrary)
- por lo general (generally)
- por supuesto (of course)
- por otra parte (on the other hand)
- por fin (finally)
- por lo menos (at least)