Portuguese has a grammatical possibility that English lacks entirely: the personal infinitive (infinitivo pessoal), an infinitive form that carries person marking. This gives Portuguese a three-way contrast in subordinate clauses that no other major European language has — between the impersonal infinitive, the personal infinitive, and the subjunctive.
The payoff of mastering this is enormous: once you understand the system, you can choose the most natural construction for any subordinate idea, often bypassing the subjunctive entirely with a lighter, more elegant infinitive clause. Native speakers lean on personal infinitives constantly. A learner who only uses the subjunctive where a personal infinitive would flow better will sound correct but mechanical.
The three-way contrast at a glance
| Construction | Used when | Example | English gloss |
|---|---|---|---|
| Impersonal infinitive | Same subject, or generic subject | Quero ir ao cinema. | I want to go to the cinema. |
| Personal infinitive | Different subject is clear, overt, or emphasized | É importante fazermos isto. | It's important for us to do this. |
| Subjunctive (finite clause) | Different subject, finite clause preferred | Quero que ele venha. | I want him to come. |
É importante fazer exercício.
It's important to do exercise. (impersonal, generic)
É importante fazermos exercício.
It's important for us to do exercise. (personal infinitive — we are the subject)
É importante que façamos exercício.
It's important that we do exercise. (subjunctive)
All three sentences are grammatical. The first is the most generic — an impersonal statement. The second foregrounds we as the doers without introducing a finite clause. The third is the most formal and emphatic.
Quick review: how the personal infinitive is formed
The personal infinitive is formed from the infinitive stem plus endings for each person. For regular verbs (all three conjugations), the forms are:
| Person | Ending | falar | comer | partir |
|---|---|---|---|---|
| eu | (none) | falar | comer | partir |
| tu | -es | falares | comeres | partires |
| ele/ela/você | (none) | falar | comer | partir |
| nós | -mos | falarmos | comermos | partirmos |
| vós | -des | falardes | comerdes | partirdes |
| eles/elas/vocês | -em | falarem | comerem | partirem |
Notice that the 1sg and 3sg are identical to the plain infinitive. What looks like an impersonal infinitive can actually be a personal infinitive — context tells you.
Even irregular verbs follow this pattern on the infinitive stem: sermos (to be, 1pl), teres (to have, 2sg), irem (to go, 3pl), fazeres (to do, 2sg).
For full paradigms and formation rules, see verbs/personal-infinitive/formation.
After verbs: same subject → impersonal infinitive; different subject → que + subjunctive
The most common structural choice in Portuguese subordination is driven by subject identity after verbs of wanting, hoping, needing, asking.
Same subject: use the impersonal infinitive
Quero ir ao teatro esta noite.
I want to go to the theatre tonight. (I want, I go)
Ela preferiu ficar em casa.
She preferred to stay home.
Precisamos de descansar.
We need to rest.
Espero ver-te em breve.
I hope to see you soon.
No que, no subjunctive — just infinitive. This parallels English "I want to go".
Different subject: use que + subjunctive
Quero que tu vás ao teatro comigo.
I want you to go to the theatre with me. (I want, you go)
Ela preferiu que ficássemos em casa.
She preferred that we stay home.
Precisamos que nos ajudes.
We need you to help us.
Espero que te lembres de mim.
I hope you remember me.
The subject changes, the connector que appears, and the verb goes into the subjunctive.
After prepositions: impersonal or personal infinitive
Portuguese prepositions cannot be followed by a finite clause directly — they must take an infinitive (or a noun). When the subject of the infinitive is the same as the main clause, use the impersonal infinitive. When it is different, use the personal infinitive.
Same subject — impersonal infinitive
Saí sem dizer nada.
I left without saying anything. (I left, I didn't say)
Antes de entrar, bate à porta.
Before going in, knock on the door. (you go in, you knock)
Depois de acabar, chama-me.
After finishing, call me.
Different subject — personal infinitive
Saí sem eles me verem.
I left without them seeing me.
Antes de tu entrares, bate à porta.
Before you go in, knock on the door.
Depois de nós acabarmos, chama-me.
After we finish, call me.
Notice how the personal infinitive eliminates the need for a finite subordinate clause. Without the personal infinitive, you would have to say "antes que tu entres" — also grammatical, but heavier. In European Portuguese, the personal infinitive after antes de, depois de, para, sem, até, por is extremely common and often preferred over the subjunctive.
The big one: para + personal infinitive (purpose clauses)
Escrevi-te para saberes a verdade.
I wrote to you so you'd know the truth.
Trabalhei muito para vocês poderem viajar.
I worked hard so you could travel.
Deixei a porta aberta para o gato entrar.
I left the door open for the cat to come in.
This construction competes directly with para que + subjunctive (para que o gato entrasse). In everyday speech, the personal infinitive is often lighter and preferred. See complex/purpose-clauses for the full treatment.
After impersonal expressions: the three-way choice
Impersonal expressions of the type é + adjective + que / infinitive (é importante, é necessário, é possível, é difícil, é urgente) admit the full three-way contrast.
Impersonal statement — generic infinitive
É importante estudar todos os dias.
It's important to study every day. (generic — anyone)
É difícil aprender uma língua sozinho.
It's hard to learn a language alone.
Specific subject with personal infinitive
É importante estudarmos todos os dias.
It's important for us to study every day.
É difícil ela aprender uma língua sozinha.
It's hard for her to learn a language alone.
É urgente fazerem uma pausa.
It's urgent that they take a break.
Specific subject with subjunctive (most formal)
É importante que estudemos todos os dias.
It's important that we study every day.
É difícil que ela aprenda uma língua sozinha.
It's difficult for her to learn a language alone.
É urgente que façam uma pausa.
It's urgent that they take a break.
All three versions are grammatical and correct. The personal infinitive version is distinctly Portuguese — neither Spanish nor French can do this — and sounds natural and polished. The subjunctive is more formal and slightly heavier.
The compound infinitive: ter + past participle
To express a completed prior action, Portuguese uses the compound infinitive ter + past participle. This applies to both the impersonal and personal infinitive.
Impersonal compound infinitive
É triste ter perdido tanto tempo.
It's sad to have wasted so much time.
Lembro-me de ter ouvido esta canção em miúdo.
I remember having heard this song as a child.
Personal compound infinitive
Depois de termos jantado, fomos passear.
After we had had dinner, we went for a walk.
Lamento teres saído tão cedo.
I'm sorry you left so early.
Foram acusados de terem mentido.
They were accused of having lied.
The compound form is extremely common in careful writing. It clarifies the temporal sequence — the subordinate action is complete before the main action — and lets you avoid the heavier antes de ter(em) feito / depois de ter(em) feito structures with finite clauses.
Ao + infinitive — upon doing
A special construction: ao (= a + o, literally "at the") + infinitive introduces a simultaneous or immediately preceding action, equivalent to English "upon, on, when".
Ao entrar, reparei que havia alguém à minha espera.
Upon entering, I noticed that someone was waiting for me.
Ao ouvir a notícia, começou a chorar.
Upon hearing the news, she began to cry.
Ao saberes isso, liga-me.
The moment you know that, call me.
Ao chegarmos a casa, já estava tudo resolvido.
When we arrived home, everything was already resolved.
Ao takes both the impersonal and the personal infinitive. This is a favourite literary and journalistic turn of phrase — it introduces the main event with elegance.
Ao + inf vs em + gerund — different aspects
Two related constructions, each with its own grammatical form:
- A / ao
- infinitive → simultaneous or punctual (as she was entering, upon entering)
- Em
- gerund → as soon as, the moment that (a literary/archaic construction)
Em entrando em casa, foi logo descansar.
As soon as he was in the house, he went straight to rest. (literary)
Em + gerund is archaic/literary in modern EP; everyday speech uses assim que + future subjunctive or ao + infinitive.
After verbs of perception (ver, ouvir, sentir)
Perception verbs can take either an infinitive or a gerund as their complement, and the infinitive can be personal if the subject is different from the main clause.
Vi o Pedro entrar.
I saw Pedro come in.
Vi-os a entrar.
I saw them coming in. (progressive)
Ouvi-os cantarem a noite toda.
I heard them singing all night. (personal inf — emphasises they were the ones singing)
Senti o vento bater-me na cara.
I felt the wind hit me in the face.
See complex/perception-verbs for the full treatment.
After causatives (fazer, mandar, deixar)
Causative verbs allow either an infinitive complement (often the impersonal) or, when the embedded subject is foregrounded, a personal infinitive.
O professor fez os alunos ficarem calados.
The teacher made the students keep quiet.
Deixei-os sair.
I let them go out.
Mandou construírem uma ponte.
He ordered a bridge to be built.
See complex/causative-constructions for full details.
The subtle art of choosing
When the subject is the same and the structure allows, use the impersonal infinitive.
When the subject is different, you often have three options:
- que
- subjunctive — most formal, obligatory with some verbs (querer que, duvidar que).
- Preposition + personal infinitive — lighter, very European, extremely natural.
- Bare personal infinitive — after impersonal expressions or as subject clauses.
The personal infinitive wins on elegance and brevity. The subjunctive wins on formality and emphasis. Both are grammatical; the choice is stylistic.
Foi um azar terem cancelado o voo.
It was bad luck that they cancelled the flight. (personal compound inf)
Foi um azar que tivessem cancelado o voo.
It was bad luck that they had cancelled the flight. (pluperfect subjunctive)
Both sentences are correct. The first is lighter and more common in speech; the second is more formal.
Infinitive clauses as subjects
A personal infinitive clause can itself be the subject of a sentence. This is a distinctly Portuguese construction.
Estudarmos juntos foi uma boa ideia.
Our studying together was a good idea.
Fazeres isso agora seria um erro.
Your doing that now would be a mistake.
Ouvirem este discurso mudou-lhes a vida.
Hearing this speech changed their lives.
English has to resort to gerunds ("our studying together", "your doing that") to match the compactness. Portuguese has a dedicated finite-flavoured infinitive that does the job.
Key contrasts with English
- English cannot mark person on infinitives. Portuguese can: para eu saber (for me to know), para tu saberes (for you to know), para ele saber (for him to know), para nós sabermos (for us to know), para eles saberem (for them to know).
- English "for X to do" roughly maps to Portuguese para
- personal infinitive: "for me to go" = para eu ir; "for them to arrive" = para eles chegarem.
- English "I want you to come" cannot be translated word-for-word. In Portuguese it must be Quero que venhas (subjunctive), never *Quero tu vires or *Quero-te vir.
- English gerunds ("upon arriving", "after finishing") usually correspond to Portuguese infinitives — not gerunds — after prepositions. "Before eating" = antes de comer, not *antes de comendo.
When the personal infinitive is NOT used
Even when the subject is different, you do not use the personal infinitive after:
- Verbs requiring que
- subjunctive (querer, desejar, pedir, ordenar, duvidar): Quero que venhas, not *Quero vires.
- Modal-style auxiliaries (poder, dever, saber): same subject is enforced.
- Most finite subordinators: quando, se, embora, logo que take a finite verb, not an infinitive.
The personal infinitive is primarily a tool of:
- Prepositional clauses (para, antes de, depois de, sem, por, até).
- Impersonal expressions (é importante, é urgente).
- Some perception/causative complements (optional).
- Subject clauses of an independent sentence.
Full summary
| Context | Construction | Example |
|---|---|---|
| After a verb, same subject | Impersonal infinitive | Quero ir. |
| After a verb, different subject | que + subjunctive (usually) | Quero que venhas. |
| After a preposition, same subject | Impersonal infinitive | Saí sem falar. |
| After a preposition, different subject | Personal infinitive | Saí sem tu falares. |
| After é + adj, generic | Impersonal infinitive | É importante estudar. |
| After é + adj, specific subject (light) | Personal infinitive | É importante estudarmos. |
| After é + adj, specific subject (formal) | que + subjunctive | É importante que estudemos. |
| Prior completed action | ter + past participle | Depois de termos jantado. |
| Simultaneous / punctual event | ao + infinitive | Ao chegar, viu-o. |
| Clause as subject | Personal infinitive | Fazeres isso seria erro. |
Common Mistakes
❌ Quero tu vires ao jantar.
Incorrect — after querer with a different subject, use que + subjunctive.
✅ Quero que venhas ao jantar.
I want you to come to dinner.
❌ É importante que estudarmos todos os dias.
Mixed construction — either que + subjunctive or personal infinitive alone.
✅ É importante estudarmos todos os dias.
It's important for us to study every day. (personal inf)
✅ É importante que estudemos todos os dias.
It's important that we study every day. (subjunctive)
❌ Antes de tu entrar, bate à porta.
Incorrect — with overt subject tu, use the personal infinitive.
✅ Antes de tu entrares, bate à porta.
Before you go in, knock on the door.
❌ Escrevi-te para tu saber a verdade.
Incorrect — with overt pronoun tu, the personal infinitive must be inflected: saberes, not saber.
✅ Escrevi-te para tu saberes a verdade.
I wrote to you so you'd know the truth.
✅ Escrevi-te para saberes a verdade.
I wrote to you so you'd know the truth. (pronoun dropped — still personal inf)
❌ Depois de nós jantar, saímos.
Incorrect — with overt nós, use the personal infinitive jantarmos.
✅ Depois de jantarmos, saímos.
After we had dinner, we went out.
❌ Saí sem eles vêem-me.
Incorrect — after sem, use the infinitive, not a finite form.
✅ Saí sem eles me verem.
I left without them seeing me.
❌ Lembro-me de ter ido ao Porto quando era pequeno mas agora eu gostaria que fazer a viagem outra vez.
Jumbled tenses/moods — should be either a que-clause or a personal infinitive construction.
✅ Lembro-me de ter ido ao Porto em pequeno, mas agora gostaria de fazer a viagem outra vez.
I remember going to Porto as a child, but now I'd like to make the trip again.
Key Takeaways
- Portuguese has a three-way contrast in subordinate clauses: impersonal infinitive, personal infinitive, and subjunctive.
- Same subject → impersonal infinitive (Quero ir). Different subject → usually que + subjunctive (Quero que vás), but after prepositions and impersonal expressions the personal infinitive is preferred.
- The personal infinitive carries person marking on the infinitive itself: ires, sabermos, fazerem.
- After prepositions (para, antes de, depois de, sem, por, até), the personal infinitive is the standard construction for different subjects.
- The compound infinitive (ter
- past participle) marks completed prior action.
- Ao
- infinitive means "upon, on, when" and is a favourite literary device.
- English cannot mark person on infinitives — this distinction is uniquely powerful in Portuguese and Galician. Once you own it, your Portuguese stops sounding translated.
Related Topics
- Personal Infinitive: OverviewB1 — The infinitivo pessoal — an infinitive that conjugates for person and number — is Portuguese's signature grammatical feature, and one of the things that makes the language feel unlike the rest of Romance.
- Personal Infinitive vs SubjunctiveB2 — Choosing between the inflected infinitive and que + conjuntivo — where the two compete, where one is forced, and what native European Portuguese speakers actually say.
- Personal Infinitive in Complex SentencesC1 — Advanced uses of the personal infinitive: absolute clauses, causative and permissive constructions, topicalization, clitic placement, and disambiguation from the future subjunctive.
- Personal Infinitive After PrepositionsB1 — The most common use of the infinitivo pessoal: after para, sem, antes de, depois de, até, and ao. Full examples of each, plus clitic placement with pronominal verbs.
- Personal Infinitive with Impersonal ExpressionsB2 — É importante nós estudarmos vs é importante que nós estudemos — a full treatment of the personal infinitive after é + adjective constructions and related impersonal triggers.
- Purpose Clauses (Para Que, A Fim De Que)B1 — Saying 'in order to / so that' in Portuguese — the split between finite (subjunctive) and non-finite (infinitive) purpose clauses.