Prepositions in Spanish are used almost in every sentence but, there are two that cause a lot of problems when students are trying to learn the language. Prepositions por and para challenge Spanish students to be very careful with their usage, because both words mean “for” in English.
In this case, the preposition por is considerably more common, so in theory, students might be able to get away with just memorizing the uses for para and then use por for everything else. But, getting to know the specific ways and situations in which they should be used is also the best way to differentiate both prepositions.
Here's the complete list of rules for when to use por and para:
The Spanish preposition por is used to indicate:
Native Spanish speakers use the preposition por when they refer to motion or a place in which the subject of the sentence is making an action at a specific moment, for example:
Ellos caminan por las calles.
They walk through the streets.
The preposition por is also used to indicate how a specific action is or has been done by the subject of the sentence, for example:
Ella envio la carta por correo aéreo.
She sent the letter by air-mail.
3. In exchange for/substitution:
Another situation in which the preposition por is used is when the subject of a sentence is doing something in exchange for something, for example:
El me dio dos lapices por mi pluma. He gave me two pencils for my pen.
or in substitution - in place of someone - like:
Voy a hacerlo por tí.
I’m going to do it for you.
4. Duration of an action:
When indicating how long an action was happening, the best preposition to use is por; it explains and supports the information given in a sentence by letting us know the duration of an action, for example:
Solamente trabaje por una hora.
I only worked for an hour.
5. Indefinite time period:
The preposition por is also used to indicate and describe a specific period of time in which some action has been happening.
The main difference between “duration of an action” and “indefinite time period” is that the first one describes an action that happened and is not happening any more, while the second one is used for an action that is still happening, for example:
Ella duerme por las tardes.
She sleeps in the afternoons.
6. On behalf of:
In Spanish, when people need to do something on behalf of someone else, the preposition por is also used, and it let us know that the person who did something is not the person who had to do it, but is also allowed to do it. A clear example would be:
La firmo por Usted.
I am signing it on your behalf.
In Spanish, it is also very important to know the details about an action that has been done or that people still do. To let other people know about these details, native Spanish speakers usually use the preposition por as an adverb that describes the action, like in the sentence:
Me pagan por día.
They pay me per day.
The Spanish preposition para is used to indicate:
The preposition para can be used to indicate destination in two different situations. The first one is to indicate a place that someone or something is heading towards, for example:
Salimos para Monterrey.
We are leaving for Monterrey.
The second situation in which the preposition para is used to indicate destination is when people talk about a person to whom something goes to, for example:
Esta carta es para Usted.
This letter is for you.
3. A future time limit:
In this situation, the preposition para is used to indicate a due date in which something has to be done, for example:
Es para mañana.
It’s for tomorrow.
The preposition para also helps to give details about the purpose or goal for which something is or has been done, for example:
Nado para divertirme.
I swim to have fun.
One of the most common situations in which the preposition para is used is to indicate the use or function for what something has been created. It can be anything, and an easy question to discover its function is “Para que sirve?” (What’s its function?) for example:
Es un cepillo para el pelo.
It’s a hair brush.
These kind of comparisons are only used when people talk about a person or thing, for example:
Para su edad, lee bien.
She reads well for her age.
The last, and also very common, situation to use the preposition para is to express your own opinion, for example:
Para mí es demasiado raro.
It’s too weird for me.
In addition, using prepositions is a an aspect of grammar that every Spanish student has to learn. The easiest way to achieve that goal? Whether with your teacher or a language partner, just get practicing, so you can remember when and where to use them!