Preposition Por: Expressing Cause, Exchange & Path
Grammar Rule in 30 Seconds
Use 'por' to describe the cause, the exchange, or the path taken during an action.
- Cause: 'Eu não fui por causa da chuva.' (I didn't go because of the rain.)
- Exchange: 'Comprei o livro por dez reais.' (I bought the book for ten reais.)
- Path: 'Caminhamos por todo o parque.' (We walked through the whole park.)
Overview
The Portuguese preposition por is a fundamental element for expressing a diverse range of relationships, primarily centered around causation, exchange, and traversal. Unlike many prepositions with highly specific meanings, por functions as a versatile connector that delineates the reason, means, path, or value associated with an action or state. While English requires multiple prepositions such as "for," "by," "through," "per," or "due to" to convey these nuances, Portuguese consolidates them efficiently within por.
Understanding por is crucial for B1 learners, as it unlocks the ability to explain motives, describe routes, detail transactions, and attribute actions. It establishes a dynamic link between elements, often indicating a "process" or a "mediation." Mastering por is key to moving beyond simple declarative sentences, allowing you to articulate the underlying mechanics and motivations behind events and actions in Portuguese. The semantic breadth of por positions it as a cornerstone for expressing complex ideas.
How This Grammar Works
por acts as a relational marker, connecting a noun, pronoun, or clause to an action or state by specifying a causal link, a medium of passage, or an equivalent value. It fundamentally answers the questions of why, how, through what, or for how much. This preposition signifies an intermediate step, a motivating factor, or a replacement.por is classified as an unstable preposition because it frequently contracts with definite articles (o, a, os, as) that follow it. These contractions are not optional stylistic choices; they are mandatory grammatical forms integral to natural Portuguese speech and writing. For instance, you would never say por a estrada (through the road) but always pela estrada.por is vast, encompassing the origin or motivation of an action (Eu fiz isso por você., "I did it for/because of you"), the means by which an action is performed (Viajamos por terra., "We traveled by land"), the path or space traversed (Passamos pela cidade., "We passed through the city"), and the concept of exchange or substitution (Troquei meu carro por uma moto., "I exchanged my car for a motorcycle"). This versatility makes por a highly frequent and indispensable word in the language.Formation Pattern
por undergoes mandatory contractions when immediately followed by a definite article. These contractions preserve the gender and number of the article, which in turn matches the noun it precedes. This phonetic assimilation is a characteristic feature of Portuguese and is crucial for sounding natural and grammatically correct.
por with the definite articles:
por + o | Masculine Singular | Pelo amor de Deus! | For the love of God! |
por + a | Feminine Singular | Pela manhã | In/During the morning |
por + os | Masculine Plural | Pelos amigos | For the friends |
por + as | Feminine Plural | Pelas regras | By the rules |
por o or por a, sounds highly unnatural and incorrect to native speakers. This rule applies consistently across all contexts where por meets a definite article. For example, if you are walking through "the streets" (as ruas), you must use pelas ruas (Andei pelas ruas do centro., "I walked through the downtown streets"). The contraction ensures fluid pronunciation and adheres to the established grammatical structure of Portuguese. This pattern is deeply ingrained in the language's phonology and morphology.
When To Use It
por is expansive, covering several core semantic functions that are essential for B1-level communication. Each usage highlights por's role in detailing the reason, path, or exchange surrounding an action.- Expressing Cause or Reason (Because of / Due to)
Por indicates the motive, cause, or reason behind an action or event. This is one of its most common and crucial applications, explaining the why. It directly links an outcome to its initiating factor.Ela chorou por tristeza.(She cried due to sadness.)O voo foi cancelado pela neblina.(The flight was canceled because of the fog.)Eu o fiz por obrigação, não por prazer.(I did it out of obligation, not for pleasure.)
- Indicating Exchange, Price, or Substitution (For / In exchange for)
por is the correct preposition. This applies to monetary transactions, bartering, or replacing one item/person with another.Comprei o livro por vinte euros.(I bought the book for twenty euros.)Troquei meu relógio velho por um novo.(I exchanged my old watch for a new one.)Ele trabalhou por mim ontem.(He worked in my place/for me yesterday.)
- Describing Path, Movement Through, or Location (Through / Along / Via)
Por is used to describe movement that passes through or along a place, or to indicate a general area of passage rather than a specific destination. It outlines the trajectory or the means of spatial navigation.Andamos pela floresta durante horas.(We walked through the forest for hours.)O ladrão entrou pela janela.(The thief entered through the window.)A rodovia passa por várias cidades históricas.(The highway passes through several historic cities.)
- Specifying Means, Method, or Agent (By / Via)
Falo com ele por telefone.(I speak with him by phone.)Enviei o documento por e-mail.(I sent the document via email.)O gol foi marcado pelo atacante.(The goal was scored by the forward.) – This illustrates the agent of a passive verb.
- Indicating Duration or Approximate Time (For / During)
Por can express a period of time during which an action occurs. In Brazilian Portuguese, especially informally, por can often be omitted in this context without losing meaning, but its inclusion is always grammatically correct.Estudei português por três anos.(I studied Portuguese for three years.)Ficaremos na praia pelo fim de semana.(We will stay at the beach for the weekend.)Ele trabalhou aqui por um longo tempo.(He worked here for a long time.)
- Expressing Distribution or Rate (Per / By the)
por functions similarly to "per" or "by the" in English.Ganho dez euros por hora.(I earn ten euros per hour.)Ele corre a dez quilômetros por hora.(He runs at ten kilometers per hour.)Vendemos os produtos pelo quilo.(We sell the products by the kilo.)
- Signifying Favor, Preference, or Alignment (For / On behalf of)
Por can convey support, preference, or representativeness, often implying an indirect benefit or choice.Eu votei por ele nas eleições.(I voted for him in the elections.)Optamos pela opção mais segura.(We opted for the safest option.)Fiz isso por você.(I did this for you [for your benefit]).
Common Mistakes
por, primarily due to its multifaceted nature and its critical distinction from para. Understanding the specific pitfalls is essential for accurate usage.- Confusing
PorwithPara: This is arguably the most pervasive error. While both can translate to "for" in English, their underlying meanings are distinct. Porindicates: cause, reason, duration, exchange, means, path, agent.Paraindicates: destination, purpose, recipient, deadline, comparison.- Mistake:
Comprei um presente para 50 reais.(Incorrect. This implies the gift is for the money.) - Correction:
Comprei um presente por 50 reais.(Correct. The money is the exchange value.) - Mistake:
Passei para o parque.(Incorrect if meaning through the park. Implies to the park as a destination.) - Correction:
Passei pelo parque.(Correct. Meaning through the park.)
- Forgetting Mandatory Contractions: Attempting to say
por o,por a,por os,por asis a common, yet glaring, error that immediately identifies a non-native speaker. These forms are grammatically incorrect in standard Portuguese. - Mistake:
Andei por a rua. - Correction:
Andei pela rua.
- Incorrectly Using
Porfor Destination or Purpose: Whileporimplies movement through a place, it does not convey the ultimate destination or goal of movement or action, which ispara's domain. - Mistake:
Vou por Lisboa.(Incorrect if meaning to Lisbon as a destination.) - Correction:
Vou para Lisboa.(Correct. Lisbon is the destination.) - Mistake:
Ele estuda por ser médico.(Incorrect.Porimplies cause, not purpose.) - Correction:
Ele estuda para ser médico.(Correct. The purpose is to become a doctor.)
- Mistaking "Thank you for..." usage: In Portuguese, the phrase for thanking someone for something always uses
por(or its contractions). - Mistake:
Obrigado para a ajuda. - Correction:
Obrigado pela ajuda.(Obrigado por + a ajuda)
Real Conversations
In everyday Portuguese, por is ubiquitous and appears in various registers, from casual texts to formal emails. Its presence often clarifies the precise nature of interactions and events.
- Explaining reasons (casual chat):
- "Não fui à festa por estar doente. Que pena!" (I didn't go to the party because of being sick. What a shame!)
- "Ele faltou pelo trabalho." (He missed it due to work.)
- Discussing transactions/prices (shopping):
- "Quanto você pagou por este casaco?" (How much did you pay for this coat?)
- "Comprei online por um preço ótimo!" (I bought it online for a great price!)
- Making plans (social media/messaging):
- "Que tal irmos pelo parque hoje? O tempo está bom." (How about we go through the park today? The weather is good.)
- "Vamos nos encontrar pela tarde, tipo 15h?" (Shall we meet in the afternoon, like 3 PM?) – This pela tarde implies "during the afternoon."
- Passive constructions (news reports/formal communication):
- "O projeto foi aprovado pelo conselho." (The project was approved by the council.)
- "A decisão foi comunicada por e-mail." (The decision was communicated by email.)
- Offering a favor/substitution (work context):
- "Posso fazer sua parte por você, sem problemas." (I can do your part for you, no problem.)
- "Você pode me enviar a apresentação por WhatsApp, por favor?" (Could you send me the presentation via WhatsApp, please?)
These examples demonstrate how por integrates seamlessly into natural discourse, conveying subtle yet crucial information about causality, means, and movement. Observing its use in authentic contexts reinforces understanding far more effectively than isolated grammar exercises.
Quick FAQ
por, addressing common areas of confusion for learners.- Q: Can I drop the
porwhen talking about duration, especially in Brazilian Portuguese?
Yes, in spoken and informal Brazilian Portuguese, por is often omitted when expressing duration. For example, "Morei lá três anos." ("I lived there three years") is very common and understood. However, including por ("Morei lá por três anos.") is always grammatically correct and often preferred in more formal contexts or in European Portuguese. The meaning remains the same, but the omission adds a layer of informality.
- Q: What about the fixed phrase
por favor? Why isn't itpelo favor?
Por favor is an idiomatic expression meaning "please," literally translating to "by favor." In this specific fixed phrase, the article o (which would lead to pelo) is omitted, and the por stands alone. This is an exception to the contraction rule, as favor here functions more as an abstract concept linked directly to por rather than requiring a definite article. It's a fossilized expression, and learners should simply memorize por favor as a unit.
- Q: Is there a difference between
porin European Portuguese (EP) and Brazilian Portuguese (BP)?
While the core meanings and contractions of por are consistent across EP and BP, there are some subtle differences in frequency and preferred usage, particularly regarding duration. As mentioned, the omission of por for duration is more common in BP. Additionally, in EP, por can sometimes be used where BP might prefer a or em for certain fixed expressions, though these are minor nuances at the B1 level. The fundamental rules of cause, exchange, and path remain universal.
- Q: When
porindicates a path, is it always physical movement?
Not exclusively. While por often describes physical traversal (Andamos pela rua.), it can also denote an abstract or metaphorical path. For instance, "Passamos por momentos difíceis." ("We went through difficult times") uses por to describe an experience or a period of time undergone, rather than a literal physical space. This flexibility highlights por's ability to describe processes and experiences.
- Q: How does
porrelate toemwhen talking about means of transport?
Both por and em can refer to means of transport, but often with a slight nuance.
Portypically emphasizes the method or channel of transport:"Viajamos por trem/carro/avião."(We traveled by train/car/plane). It describes the mode.Emusually implies being inside the vehicle:"Viajamos no trem/carro/avião."(We traveled in the train/car/plane). It focuses on the location within the vehicle.Emcontracts with articles, leading tono,na,nos,nas. While both are often interchangeable,poris generally more direct for stating the means of travel.
Contractions of 'Por'
| Preposition | Article | Contraction | Gender/Number |
|---|---|---|---|
|
por
|
o
|
pelo
|
Masculine Singular
|
|
por
|
a
|
pela
|
Feminine Singular
|
|
por
|
os
|
pelos
|
Masculine Plural
|
|
por
|
as
|
pelas
|
Feminine Plural
|
Common Usage Patterns
| Usage | Structure | Example |
|---|---|---|
|
Cause
|
por + noun
|
por medo
|
|
Price
|
por + value
|
por dez reais
|
|
Path
|
por + location
|
pela rua
|
Meanings
The preposition 'por' is a versatile tool used to indicate the reason for an action, the price of an exchange, or the physical path through which movement occurs.
Cause/Reason
Indicates the motivation or cause behind an event.
“Ele chorou por tristeza.”
“Não saí por preguiça.”
Exchange/Price
Used when trading one thing for another or paying a price.
“Troquei meu carro por uma moto.”
“Vendi o relógio por cem euros.”
Path/Movement
Describes movement through, across, or along a space.
“Passamos por um túnel.”
“Eles caminham por toda a cidade.”
Reference Table
| Form | Structure | Example |
|---|---|---|
|
Affirmative
|
por + noun
|
Vou por aqui.
|
|
Negative
|
não + por + noun
|
Não fiz por mal.
|
|
Question
|
Por que + verb
|
Por que você veio?
|
|
Contraction
|
pelo/pela
|
Caminhei pela praia.
|
|
Duration
|
por + time
|
Estudei por horas.
|
|
Exchange
|
por + object
|
Troquei por um novo.
|
Formality Spectrum
Agradeço por tudo. (Social)
Obrigado por tudo. (Social)
Valeu por tudo. (Social)
Valeu por tudo, cara! (Social)
The Three Pillars of Por
Cause
- por medo out of fear
Exchange
- por dinheiro for money
Path
- pela rua through the street
Examples by Level
Eu ando pelo parque.
I walk through the park.
Obrigado por tudo.
Thanks for everything.
Eu vou por aqui.
I go this way.
Não saio por chuva.
I don't go out because of rain.
Comprei o pão por dois euros.
I bought the bread for two euros.
Estudei por três horas.
I studied for three hours.
Passamos pela praça.
We passed through the square.
Falo por telefone.
I speak by phone.
Lutei por este emprego.
I fought for this job.
O carro passou pelos sinais.
The car passed through the signals.
Fiz isso por você.
I did this for you.
Eles foram pelas ruas antigas.
They went through the old streets.
O projeto foi aprovado por todos.
The project was approved by everyone.
Por mais que eu tente, não consigo.
As much as I try, I can't.
Viajamos por toda a Europa.
We traveled throughout Europe.
Troquei a casa por um apartamento.
I traded the house for an apartment.
Porquanto seja difícil, continuaremos.
Inasmuch as it is difficult, we will continue.
Ele foi visto porventura na cidade.
He was seen by chance in the city.
Por fim, chegamos ao destino.
Finally, we arrived at the destination.
O documento foi assinado por procuração.
The document was signed by proxy.
Por entre as árvores, via-se o sol.
Through the trees, one could see the sun.
Por mais que se argumente, a lei é clara.
No matter how much one argues, the law is clear.
Ele agiu por conta própria.
He acted on his own account.
Porventura virá amanhã?
By any chance will he come tomorrow?
Easily Confused
Both are prepositions that often translate to 'for' or 'to' in English.
They sound identical but have different functions.
Both can express time.
Common Mistakes
Vou por a casa.
Vou para a casa.
Caminhei por a rua.
Caminhei pela rua.
Por que você vai?
Por que você vai?
Comprei por 5 reais.
Comprei por 5 reais.
Estudei para duas horas.
Estudei por duas horas.
Obrigado para tudo.
Obrigado por tudo.
Fui pelo parque para caminhar.
Fui pelo parque para caminhar.
O livro foi escrito para o autor.
O livro foi escrito pelo autor.
Vou viajar por Brasil.
Vou viajar pelo Brasil.
Fiz isso por que você pediu.
Fiz isso porque você pediu.
Porventura ele não virá.
Porventura ele virá?
Porquanto ele é rico, não trabalha.
Porquanto ele é rico, trabalha.
Ele agiu por conta dele.
Ele agiu por conta própria.
Por entre as nuvens, o sol.
Por entre as nuvens, o sol.
Sentence Patterns
Eu fiz isso ___ ___.
Eu passei ___ ___.
Eu comprei por ___ ___.
___ ___ você fez isso?
Real World Usage
Obrigado por tudo!
Passei por várias experiências.
Vou viajar pela costa.
Quanto por este item?
Postado por mim.
Entregue por João.
Check the article
Don't confuse with Para
Duration
Regional variation
Smart Tips
Use 'por' instead of 'durante' for a more natural flow.
Always check if you need a contraction (pelo/pela).
Use 'por' for short, punchy reasons.
Use 'por' to introduce the person doing the action.
Pronunciation
Stress
The word 'por' is a monosyllable and is usually unstressed unless emphasized.
Question
Por que você veio? ↗
Rising intonation at the end for questions.
Memorize It
Mnemonic
Remember 'P-E-P': Path, Exchange, and Purpose (Cause).
Visual Association
Imagine a person walking through a tunnel (Path), holding a coin to trade (Exchange), and explaining why they are there (Cause).
Rhyme
Para is for where you go, Por is for the path you know.
Story
Maria walked through the park (pelo parque) to buy a gift for her friend. She paid for it (por) with her savings. She did it because she loves her friend (por amor).
Word Web
Challenge
Write 3 sentences using 'por' in the next 5 minutes: one for a reason, one for a price, and one for a path.
Cultural Notes
In Brazil, 'pelo' and 'pela' are used constantly. In informal speech, people might drop the 'r' in 'por' before consonants.
European Portuguese speakers are very precise with contractions. You will hear 'pelo' and 'pela' clearly articulated.
Usage is similar to Portugal, with a focus on formal structures in writing.
Comes from the Latin 'per', meaning 'through'.
Conversation Starters
Por que você está aprendendo português?
Por onde você gosta de caminhar?
Você já trocou algo por algo melhor?
Por que você acha que o português é importante?
Journal Prompts
Common Mistakes
Test Yourself
Caminhei ___ (por + a) rua.
Vou ___ (por/para) Lisboa amanhã.
Find and fix the mistake:
Fiz isso por que você pediu.
Arrange the words in the correct order:
All words placed
Click words above to build the sentence
I bought it for 10 euros.
Answer starts with: Com...
Match each item on the left with its pair on the right:
por + os
Use 'por' to explain why you are late.
Score: /8
Practice Exercises
8 exercisesCaminhei ___ (por + a) rua.
Vou ___ (por/para) Lisboa amanhã.
Find and fix the mistake:
Fiz isso por que você pediu.
por / tudo / obrigado / você
I bought it for 10 euros.
1. Por medo, 2. Pela rua, 3. Por 5 reais
por + os
Use 'por' to explain why you are late.
Score: /8
Practice Bank
12 exercisesNós viajamos ___ Espanha ano passado.
Vou enviar o arquivo ___ WeTransfer.
Which sentence indicates time duration?
Fiz isso para amor, não para dinheiro.
Match the components to the result:
caminhar / gosto / praia / de / pela
Translate: 'For the love of God!'
Select the sentence implying movement through/across:
Obrigado para tudo.
Elas foram elogiadas ___ professor.
Choose the best translation:
Translate the sentence.
Score: /12
FAQ (8)
Usually, yes. You can also use 'por causa de', but 'por' is more concise.
Yes, for duration (e.g., 'por duas horas').
It's a historical evolution to make speech flow better.
No, they are distinct. 'Para' is for goals, 'por' is for paths and causes.
When 'por' is followed by 'o'.
Yes, to indicate the agent (e.g., 'feito por mim').
No, that's 'para'.
It's neutral and used in all registers.
Scaffolded Practice
1
2
3
4
Mastery Progress
Needs Practice
Improving
Strong
Mastered
In Other Languages
por
Contractions are more frequent in Portuguese.
par / pour
French 'pour' covers both purpose and reason.
durch / für
German grammar relies on cases (accusative/dative) rather than simple prepositions.
ni / de / tame ni
Japanese is agglutinative; particles follow the noun.
bi / li
Arabic prepositions are often attached to the word.
yīnwèi / tōngguò
Chinese lacks the prepositional contraction system.
Learning Path
Prerequisites
Continue With
Portuguese Preposition 'Por': Expressing Cause & Reason
Overview The Portuguese preposition `por` is fundamental for expressing cause, reason, motive, and origin. It functions...
Portuguese Prepositions: Through and Along (Por)
Overview The Portuguese preposition `por` is a multifaceted word, critical for articulating various relationships, inclu...
Portuguese Preposition 'Por': Means, Methods, and Agents
Overview The Portuguese preposition `por` is a highly versatile and fundamental word, essential for expressing complex r...
Portuguese 'Por': Swapping & Buying (In Exchange For)
Overview The Portuguese preposition `por` is a fundamental and highly versatile linguistic tool, primarily used to expre...
Saying 'Per' or 'By': Rates with Por (por dia, pelo quilo)
Overview When navigating the quantitative landscape of Portuguese, from stating frequencies to delineating pricing struc...
Por for Time (Duration & Approximation)
Overview In Portuguese, the preposition `por` is a multifaceted tool, especially when navigating temporal expressions. A...
Por vs. Para: Doing Favors & Swapping
Overview Prepositions like `por` and `para` are fundamental to Portuguese grammar, acting as essential connectors that d...
Related Videos
Related Grammar Rules
The Conditional 'Se' (If)
Overview The conditional conjunction `se` in Portuguese serves as the direct equivalent of "if" in English, introducing...
Portuguese Verb Regimen: Using the Right Prepositions (Regência Verbal)
Overview Portuguese `Regência Verbal` defines the precise relationship between a verb and its complements. Unlike Englis...
Advanced Connectors: Result & Consequence (tão... que, de modo que)
Overview As you advance in Portuguese, moving towards the C1 level, your goal shifts from merely being understood to exp...
Asking 'Why' in Portuguese (Por que)
Overview Portuguese, like English, requires a precise way to ask "why." For learners at the A1 (Beginner) CEFR level, **...
Por vs. Para: Doing Favors & Swapping
Overview Prepositions like `por` and `para` are fundamental to Portuguese grammar, acting as essential connectors that d...
