“Por” is a preposition. There are several prepositions in English that mean “por” in Spanish. The Spanish Academy has a long list of the meanings of por. Although this list is intended for native speakers, most examples are very easy to understand.
One of the most common problems for non-native speakers of Spanish is to use por and para correctly. The main problem is that both prepositions have more than ten meanings each! One more problem is that “por” sounds a lot like “for.” I will attempt to give you a hint of when to use “por.” On a later post, I will attempt to do the same with “para.”
Por comes from “pro” and “per” in Latin. Therefore, most of the time “per” in English will mean “por” in Spanish. It also means exchange, because, about to do something, percentage, duration of time or lapse of time, going by or around a place when the name of the place comes after “por,” ways or means of communication, passive voice (made by X), counting by, and why. There are also several idiomatic expressions with por. Here are a few of them:
por ejemplo (for example)
por favor (please)
por Dios (by God)
por lo menos (at least)
por lo general (in general)
por nada (for nothing, or it's nothing)
gracias por todo (thanks for everything)
por lo visto (evidently)
Whenever I explain por and para in the classroom, I tell the students that I'm a cavewoman for that class. I draw childish symbols and figures on the board. I also make some of those drawings with my hand when I'm speaking. I walk around the classroom to give a better idea of por (walking by, going around).
Here are my POR drawings:
Reason, why something happens.
Lo hago por amor. = I do it because of love.
Fuimos a Toledo por la fiesta de Andrea. - We went to Toledo because of Andrea's party.
About to do something.
Estoy por comprar una casa en Santiago. = I'm about to buy a house in Santiago.
Estamos por salir. = We're about to leave.
Math (times) and exchange/substitution.
2 x 3 = 6 – Dos por seis es igual a seis. Two times three is six.
Mi madre trabajó por mi tía ayer. - My mother worked instead of my aunt yesterday.
20% = veinte por ciento – twenty per cent.
El dólar está a 10 pesos por un dólar. The dollar is 10 pesos for one dollar.
Ellos pagaron mucho dinero por la casa. They paid a lot of money for the house. (exchange of money)
Se fueron de la fiesta uno por uno. - They left the party one by one.
Time (duration of time).
Me baño por cinco minutos. - I bathe for five minutes.
Dormí por 10 horas el sábado pasado. - I slept for 10 hours last Saturday.
Fuimos de vacaciones por una semana. - We went on vacation for a week.
Ways or means of communication and transportation.
Ellos hablan por teléfono y por correo electrónico. - They talk by phone and by email.
Enviamos la carta por correo certificado. - We sent the letter by certified mail.
Carlos salió por tren a Nueva York. - Carlos left by train to New York.
Tú vas por carro a las montañas. You go by car to the mountains.
To go arround a place or to pass by a place
Ustedes pasaron por mi casa anoche. - You all passed by (or around) my house last night.
Vamos por la carretera I-95 de Richmond a Atlanta. - We go by I-95 from Richmond to Atlanta. (We use, we go by the highway)
Dimos la vuelta por la manzana de tu casa. – We went around the block where your house is.
Passive voice / the author/director of something.
El libro fue escrito por Augusto Monterroso. - The book was written by Augusto Monterroso.
El dibujo fue hecho por Lulú. - The drawing was made by Lulú.
Dirigida por Robert Rodríguez. - Directed by Robert Rodríguez.
Patrocinado por la letra X. - Sponsored by the letter X.
In some cases, we don't need “por” even if the phrase in English sounds like we need it in Spanish. Usually is a verb in English that needs the preposition “for.”
To pay for – pagar - They pay for the tacos. - Ellos pagan los tacos.
To look for – buscar – I'm looking for a book. - Estoy buscando un libro.
To search for – buscar – They looked for the dog on the street. Ellos buscaron al perro en la calle.
To wait for – esperar – My aunt was waiting for my mother. - Mi tía estaba esperando a mi madre.
However, sometimes we use por with pagar. Consider this example:
¿Cuánto dinero pagaste por ese juguete? - How much money did you pay for that toy?
Here we need “por” because there is a more specific exchange, money for a toy.
And “to thank for” needs por:
Gracias por el libro. - Thanks for the book.
Por nada. - You're welcome.
Basically, por means: reason, exchange, substitution, percentage, per, multiplication, done by X person, going around, going by, communicating by, time duration, and about to do X.
I hope this helps. If it does, please write a comment.