The third major cluster of por uses has to do with substitution and exchange — one thing standing in for another. This cluster covers payment, acting on someone else's behalf, and the "by" of passive sentences.
Exchange: something for something
The clearest case: you give X and get Y in return. The thing you give — the price, the trade, the substitute — goes with por.
Compraron la casa por doscientos mil dólares.
They bought the house for two hundred thousand dollars.
In all three sentences, por marks what you give up (money, sandwich, money again) in exchange for something else. English also uses "for" here, and in this specific sense the English "for" and Spanish por line up perfectly.
por, not para. "Lo compré para cinco dólares" is wrong; it has to be "por cinco dólares."On behalf of / in place of
Por also means "in place of" or "on behalf of" — acting as a substitute for another person.
La profesora dio la clase por su colega enfermo.
The teacher taught the class in place of her sick colleague.
This is another case where English "for" maps to Spanish por. You're substituting yourself for the absent person.
"For" as in "on behalf of a cause"
Luchó toda su vida por los derechos humanos.
She fought her whole life for human rights.
This is halfway between the "cause" meaning we covered earlier and the "on behalf of" meaning. The person fights because of human rights (cause) and on behalf of them (substitution). Both readings use por.
Passive agent: "by" the author
When you use a true passive construction (ser + past participle), the agent who performed the action is introduced with por. English uses "by" here, Spanish uses por:
Cien años de soledad fue escrito por Gabriel García Márquez.
One Hundred Years of Solitude was written by Gabriel García Márquez.
La ciudad fue fundada por los españoles en 1537.
The city was founded by the Spaniards in 1537.
El cuadro fue pintado por Frida Kahlo.
The painting was painted by Frida Kahlo.
Note that Spanish uses true passive sentences less often than English. In everyday conversation, Spanish usually prefers active voice or the se passive: La ciudad se fundó en 1537. But when passive is used, the agent comes with por.
"Por" with verbs of motion toward: go get
A subtle but useful structure: ir por X or venir por X means "to go/come for X" — that is, to go in order to fetch something. You'll also hear ir a por X, especially in Spain, but in Latin America the plain ir por X dominates.
Voy por el pan, vuelvo en cinco minutos.
I'm going to get the bread, I'll be back in five minutes.
Ya vine por mi mochila, gracias.
I've come to pick up my backpack, thanks.
This feels a bit like the "exchange" meaning: you're "going in exchange for" (or rather, in pursuit of) the bread.
Common expressions with this por
| Expression | Meaning |
|---|---|
| por favor | please (literally: for a favor) |
| por suerte | luckily (by stroke of luck) |
| por desgracia | unfortunately |
| cambiar X por Y | to exchange X for Y |
| votar por | to vote for |
| dar las gracias por | to thank for |
Wrapping up por
Between por for cause, por for movement and rates, and this page on exchange, you've seen the main uses of por. There are a few more tucked into idioms and fixed expressions, but these three clusters will get you through almost every real-world sentence.
por points backward (at the cause, the origin, or the thing being given up), while para points forward (toward a goal, destination, or recipient). Keeping this "backward vs forward" image in mind helps in borderline cases.Next we'll look at para and then do a full side-by-side comparison of the two. Start with para: purpose and goal.
Related Topics
- Por: Cause, Reason, MotiveB1 — Using por to express why something happens — the cause, reason, or motivation behind an action
- Por: Through, Along, PerB1 — Using por for movement through a space, along a path, and for rates or approximate locations
- Por vs Para: Complete ComparisonB1 — Side-by-side comparison of when to use por and when to use para, with a mnemonic and examples