Por looks forward to an intended goal: a beneficiary, recipient, use, purpose, or exchange. Pro looks backward to a cause or motive that explains why something happens. English for can express either direction, so translating that one word mechanically produces many avoidable errors.
The time-arrow test
Ask where the relationship points:
- por → a wanted result, intended use, or person meant to benefit;
- pro ← an existing cause, circumstance, or motive that produces the situation.
Mi laboris tutan vesperon por la prezento.
I worked all evening for the presentation, in order to prepare it.
Mi laboris hejme pro la neĝŝtormo.
I worked at home because of the snowstorm.
The presentation is the goal organizing the work. The storm is the circumstance that caused the location choice.
Por for purpose and intended result
With a noun phrase, por can name the purpose or intended use of an object or action.
Ni rezervis apartan ĉambron por la infanaj agadoj.
We reserved a separate room for the children’s activities.
Ĉu ĉi tiu programo taŭgas por redakti sondosierojn?
Is this program suitable for editing audio files?
Ŝi ŝparas monon por longa vojaĝo tra Azio.
She is saving money for a long trip through Asia.
The goal need not actually be reached. Por marks intention, suitability, or planned use, not successful outcome.
With an infinitive, por expresses the subject’s purpose. The understood subject of the infinitive is normally the subject of the main verb.
Mi telefonis al la hotelo por konfirmi la rezervon.
I called the hotel to confirm the reservation.
Ni haltis ĉe la apoteko por aĉeti bandaĝojn.
We stopped at the pharmacy to buy bandages.
The caller confirms; the people who stop also buy. When the intended action has a different explicit subject, use por ke + finite clause, commonly with the volitive -u because the clause expresses a desired outcome.
Mi sendis mapon por ke la gastoj trovu la domon senprobleme.
I sent a map so that the guests could find the house without difficulty.
The purpose-clause guide covers same-subject and different-subject choices in detail.
Por for beneficiary and intended recipient
Por identifies the person or group whose benefit, use, or eventual possession is intended.
Mi lasis pecon da kuko por vi en la fridujo.
I left a piece of cake for you in the refrigerator.
La urbo konstruas novan ludejon por junaj infanoj.
The city is building a new playground for young children.
Compare al, which marks an actual destination or recipient. Mi sendis la dosieron al Nora says Nora received or was the destination of the sending. Mi preparis la dosieron por Nora says it was intended for her, whether or not it has reached her.
La pakaĵo estas por Mateo, sed bonvolu doni ĝin al lia fratino.
The package is for Mateo, but please give it to his sister.
One phrase identifies intended beneficiary; the other identifies the actual recipient of the transfer.
Pro for physical causes and circumstances
Pro introduces something already present that brings about an event, state, or decision.
La matĉo estis prokrastita pro forta pluvo.
The match was postponed because of heavy rain.
Ŝi ne povis dormi pro la bruo de la lifto.
She could not sleep because of the noise from the elevator.
Kial la strato estas fermita? — Pro rompita akvotubo.
Why is the street closed? — Because of a broken water pipe.
The cause can be favorable, unfavorable, deliberate, or accidental. Pro itself does not mean “blame.” Context supplies the evaluation.
Pro for motives and grounds
A person’s feeling, belief, or reason for acting can also be a cause.
Li rifuzis la oferton pro principaj kialoj.
He refused the offer for reasons of principle.
Mi demandis nur pro scivolemo, ne por kritiki vin.
I asked only out of curiosity, not in order to criticize you.
The second sentence is a particularly useful contrast. Pro scivolemo gives the motive already prompting the question; por kritiki names a denied intended goal.
Thanks, praise, apology, punishment, and reward commonly take pro because they react to a reason or deed.
Koran dankon pro via rapida kaj klara respondo.
Many thanks for your prompt and clear reply.
Mi pardonpetas pro la konfuzo pri la dato.
I apologize for the confusion about the date.
The English for in these fixed social acts points backward to the reason for gratitude or apology, so pro is coherent rather than idiomatic exception.
The same noun can follow either word
Changing the preposition changes the causal direction.
Mi faris tion por vi.
I did that for your benefit.
Mi faris tion pro vi.
I did that because of you.
The first is beneficiary-oriented and usually supportive. The second says the person was the cause or motive; it can be affectionate, neutral, or accusatory depending on context.
Ili kolektas monon por la nova kliniko.
They are raising money for the new clinic.
Ili kolektas monon pro la krizo en la loka kliniko.
They are raising money because of the crisis at the local clinic.
The future clinic is a goal. The current crisis is a cause.
Por tio, ke and pro tio, ke
When the purpose or cause is a full clause, tio, ke can make the prepositional relationship explicit.
Ni laboras por tio, ke ĉiuj dokumentoj estu rete alireblaj.
We are working so that all documents will be accessible online.
La teamo malfruis pro tio, ke la trajno paneis.
The team was late because the train broke down.
For purpose, simple por ke is normally lighter than por tio, ke. For cause, ĉar is often lighter than pro tio, ke. The expanded forms are useful when contrast, parallel structure, or a governing preposition must remain explicit. They are neutral, with somewhat greater frequency in careful (formal) prose.
Exchange, price, and compensation
Por commonly marks what is received or given in an exchange and the price paid for something.
Ni pagis kvindek eŭrojn por la uzita tablo.
We paid fifty euros for the used table.
Ŝi interŝanĝis sian noktan deĵoron por libera vendredo.
She exchanged her night shift for a free Friday.
Attested usage sometimes has pro with payment or compensation, especially when the work or item is construed as the grounds for payment. Both are established in that limited area. For learners, pagi prezon por io is the clearest exchange frame, while ricevi rekompencon pro ago clearly presents the action as grounds for a reward.
La volontuloj ricevis premion pro sia multjara laboro.
The volunteers received an award for their many years of work.
This overlap does not weaken the central purpose-versus-cause distinction; it shows that commercial and reward situations can be conceptualized from either side.
English for often requires neither
Do not force every English for into this pair:
- duration: dum tri semajnoj, not ordinary por tri semajnoj;
- actual recipient: sendi al ŝi;
- topic: libro pri birdoj;
- replacement: anstataŭ mi;
- support: voĉdoni favore al la propono or contextually por la propono.
Ni loĝis en la vilaĝo dum ses monatoj.
We lived in the village for six months.
The decision begins with Esperanto meaning, not with choosing between two dictionary equivalents.
Decision flow
- Does the phrase explain an existing cause, motive, grounds, or trigger? Choose pro.
- Does it express a desired future result, intended use, beneficiary, or exchange? Choose por.
- Is the complement an action by the same subject? Use por + infinitive.
- Is the intended action performed by another explicit subject? Use por ke + finite verb.
- If English merely has for, test whether Esperanto instead needs dum, al, pri, or another relation.
Both prepositions are foundational and neutral in every register. The intended semantic direction, not formality, decides most cases.
Common Mistakes
Using por for an existing cause
❌ La flugo estis nuligita por densa nebulo.
Incorrect — the fog caused the cancellation; it was not its purpose.
✅ La flugo estis nuligita pro densa nebulo.
The flight was canceled because of dense fog.
Using pro for intended benefit
❌ Mi aĉetis ĉi tiun libron pro mia nevino.
Incorrect for a gift intended for the niece — this says she caused the purchase.
✅ Mi aĉetis ĉi tiun libron por mia nevino.
I bought this book for my niece.
Copying English for in an apology
❌ Pardonu min por la malfrua respondo.
Incorrect in the neutral reason frame — the late response is what prompts the apology.
✅ Pardonu min pro la malfrua respondo.
Forgive me for the late reply.
Using por instead of dum for duration
❌ Ili atendis por du horoj antaŭ la enirejo.
Incorrect — this is elapsed duration, not purpose.
✅ Ili atendis dum du horoj antaŭ la enirejo.
They waited for two hours outside the entrance.
Using por + infinitive with the wrong understood subject
❌ Mi malfermis la pordon por la gastoj eniri.
Incorrect in neutral Esperanto — the infinitive would normally share the main subject.
✅ Mi malfermis la pordon por ke la gastoj eniru.
I opened the door so that the guests could enter.
Key Takeaways
Por points toward intention, benefit, use, or exchange. Pro points back to cause, motive, or grounds. Track the direction of explanation, rebuild purpose clauses according to their subject, and do not assume that every English for belongs to either preposition.
Related Topics
- PorB2 — Use por for an intended beneficiary, purpose, use, result, exchange, or the goal toward which an action is directed.
- ProB2 — Use pro for cause and motive, while distinguishing reasons from purposes and recognizing traditional exchange uses.
- Purpose Clauses with Por KeA2 — Express intended outcomes with por ke and the volitive, and choose correctly between a finite purpose clause and por plus an infinitive.
- Cause ClausesA2 — Explain reasons and motives with finite ĉar clauses while distinguishing them from pro phrases, tial, and coordinating links.
- Thanks and ResponsesA2 — Thank someone naturally in Esperanto, state the reason and recipient clearly, and choose an appropriate response.
- Infinitives after PrepositionsA2 — Choose the established preposition-plus-infinitive patterns and replace disfavored combinations with clauses, participles, or action nouns.