The personal infinitive (infinitivo pessoal) is the single most distinctive feature of Portuguese grammar. No other mainstream Romance language has it — not Spanish, not Italian, not French, not Romanian. Only Portuguese and its close sister Galician inflect the infinitive for person and number, and when you use it well, your Portuguese instantly sounds like Portuguese rather than translated Spanish.
The core idea: Portuguese offers you two infinitives. The impersonal infinitive is the dictionary form — falar, comer, partir — and it never changes. The personal infinitive is the same form with person-and-number endings added — falar, falares, falar, falarmos, falarem — and it agrees with a specific subject. Your job is to know when each one is required, when they alternate, and when picking the wrong one will mislead your listener.
The forms at a glance
For all regular verbs and most irregular ones, the personal infinitive is built by taking the impersonal infinitive and adding the endings -Ø, -es, -Ø, -mos, -em.
| Person | falar (to speak) | comer (to eat) | partir (to leave) |
|---|---|---|---|
| eu | falar | comer | partir |
| tu | falares | comeres | partires |
| ele / ela / você | falar | comer | partir |
| nós | falarmos | comermos | partirmos |
| eles / elas / vocês | falarem | comerem | partirem |
A striking fact about the personal infinitive: even famously irregular verbs like ser, estar, ir, ter, pôr inflect in this regular way. Ser gives ser, seres, ser, sermos, serem; ir gives ir, ires, ir, irmos, irem; pôr gives pôr, pores, pôr, pormos, porem. There is no separate irregular personal-infinitive paradigm to memorise — the only work is in recognising when to reach for it.
The quick decision
Ask yourself two questions in order:
1. Does the infinitive clause have a subject different from the main clause? If yes → personal infinitive.
2. Is the subject the same, and the infinitive comes right after a modal or volition verb (querer, poder, saber, ter de, dever)? If yes → impersonal infinitive.
Everything else is a tendency rather than a hard rule, and we will work through those below.
When the personal infinitive is required or strongly preferred
1. The infinitive clause has its own subject
This is the clearest trigger. Whenever the subject of the infinitive is different from the subject of the main verb — or even just made explicit in the infinitive clause — Portuguese prefers the personal infinitive.
É importante eles chegarem cedo à reunião.
It's important that they arrive early at the meeting.
O professor mandou-nos irmos à secretaria.
The teacher told us to go to the office.
É raro a Ana faltar às aulas.
It's rare for Ana to miss classes.
The personal infinitive lets Portuguese express "for X to do Y" in a single clean clause, without the heavier que-subjunctive alternative. Spanish cannot do this — es importante que ellos lleguen temprano with a subjunctive is the only option. Portuguese gives you both.
2. After prepositions, when clarity about the subject matters
When an infinitive follows a preposition (para, sem, por, até, ao, depois de, antes de, apesar de), the personal infinitive clarifies who is performing the action — especially if it differs from the main subject.
Para eu compreender, tens de me explicar outra vez.
For me to understand, you have to explain it again.
Ao sairmos do cinema, começou a chover.
As we left the cinema, it started raining.
Sem eles saberem, preparámos-lhes uma festa surpresa.
Without them knowing, we prepared a surprise party for them.
Agradeço-te imenso por me teres ajudado ontem.
Thank you so much for having helped me yesterday.
Note that last one uses the compound personal infinitive (teres ajudado) — formed with the personal infinitive of ter + past participle. This is common after por and depois de when the action is already completed.
3. After perception and causative verbs
Verbs of perception (ver, ouvir, sentir) and causatives/permissives (mandar, deixar, fazer, ajudar) take the personal infinitive when the infinitive's subject is mentioned.
Vi-os entrarem no café à pressa.
I saw them go into the café in a hurry.
Deixei os miúdos brincarem no jardim.
I let the kids play in the garden.
Ouvi-a chorar toda a noite.
I heard her cry all night. (single subject pronoun — impersonal; but 'ouvi as crianças chorarem' with a lexical subject prefers personal)
With a clitic pronoun as the subject of the infinitive (vi-os, ouvi-a), native speakers sometimes use the impersonal form and sometimes the personal form. Both are attested. With a full noun phrase (vi as crianças, mandei os alunos), the personal infinitive is strongly preferred.
4. After impersonal expressions (é preciso, é melhor, é difícil)
When impersonal expressions take an infinitive complement with an explicit subject, the personal infinitive is the natural choice.
É preciso estudares mais antes do exame.
You need to study more before the exam.
É melhor irmos embora agora, está a ficar tarde.
We'd better leave now, it's getting late.
Foi difícil eles aceitarem a decisão.
It was hard for them to accept the decision.
5. As a stylistic alternative to que + conjuntivo
In many contexts where a learner might reach for que + conjuntivo, a native speaker will prefer the personal infinitive because it is shorter and flows better. The meaning is the same.
É importante que eles cheguem cedo.
It's important that they arrive early. (que + conjuntivo — grammatical, slightly heavier)
É importante eles chegarem cedo.
It's important for them to arrive early. (personal infinitive — more elegant in PT-PT)
Para que compreendas, vou repetir.
So that you understand, I'll repeat. (formal, conjuntivo)
Para compreenderes, vou repetir.
For you to understand, I'll repeat. (personal infinitive — more natural in speech)
PT-PT speech, especially, leans on the personal infinitive wherever it is available. Overusing the conjuntivo where the personal infinitive would do sounds stilted.
When the impersonal infinitive is used
1. Same subject, single clause
When the subject of the main verb and the infinitive are the same, and the infinitive follows directly with no intervening subject, the impersonal form is correct — and using the personal form here sounds wrong.
Espero chegar a tempo.
I hope to arrive on time.
Preferimos ficar em casa esta noite.
We'd rather stay home tonight.
Adding a personal ending here would be ungrammatical: ❌ Queremos falarmos com o teu pai.
2. After modal verbs and semi-modals
Modals (poder, dever, saber, ter de/que, haver de, costumar) always take the impersonal infinitive. These verbs form a tight unit with their complement, leaving no room for inflection.
Posso falar contigo um minuto?
Can I speak with you for a minute?
Tenho de ir ao médico amanhã.
I have to go to the doctor tomorrow.
Costumamos jantar cedo durante a semana.
We usually eat dinner early during the week.
Even when the subjects of a chain of modals differ, the modal itself carries the inflection, not the infinitive.
3. Fixed expressions and lexicalised phrases
Several set phrases always use the impersonal infinitive:
| Expression | Meaning |
|---|---|
| a não ser que | unless |
| por assim dizer | so to speak |
| para dizer a verdade | to tell the truth |
| ter a ver com | to have to do with |
| isto é, a saber | that is, namely |
Venho amanhã, a não ser que chova.
I'm coming tomorrow, unless it rains.
Ela é, por assim dizer, a alma do grupo.
She is, so to speak, the heart of the group.
4. The subject is generic or unspecified
When the infinitive expresses a general principle with no specific subject, the impersonal is used — this is the "bare" infinitive as a noun or command-like form.
Fumar faz mal à saúde.
Smoking is bad for your health.
Não estacionar.
No parking. (sign)
Comer fruta todos os dias é importante.
Eating fruit every day is important.
The contrast with que + conjuntivo
Many sentences allow both the personal infinitive and que + conjuntivo. The meanings are equivalent; the register and rhythm differ.
| Que + conjuntivo | Personal infinitive | English |
|---|---|---|
| É importante que eles cheguem cedo. | É importante eles chegarem cedo. | It's important for them to arrive early. |
| Para que possas ouvir melhor… | Para poderes ouvir melhor… | So that you can hear better… |
| Antes de que eles partam… | Antes de eles partirem… / Antes de partirem… | Before they leave… |
| Apesar de que estejas cansado… | Apesar de estares cansado… | Despite your being tired… |
In everyday PT-PT, the personal infinitive is usually preferred in these alternations for spoken and written prose alike. The que-subjunctive sounds formal to the point of bookish. Use it when you want to emphasise the subjunctive's modal force (wish, command, doubt); otherwise, reach for the personal infinitive.
Walking through the decision tree
1. Eu quero _ (falar) com a Maria. → same subject, volition verb → impersonal → falar.
2. É bom _ (nós / chegar) cedo à festa. → different/explicit subject after impersonal expression → personal → chegarmos.
3. Para _ (tu / perceber), tens de ler devagar. → preposition + explicit subject → personal → perceberes.
4. Vi os alunos _ (sair) da sala. → perception verb + lexical subject → personal → saírem.
5. Tenho de _ (ir) ao banco. → modal ter de → impersonal → ir.
6. Ao _ (nós / chegar) ao hotel, já era tarde. → preposition ao + subject → personal → chegarmos.
7. É proibido _ (fumar) neste edifício. → generic, no subject → impersonal → fumar.
8. Agradeço-te por _ (tu / ter vindo). → preposition + subject, past action → compound personal → teres vindo.
Comparison with English and Spanish
English has nothing like the personal infinitive. The closest construction is the for + subject + to pattern: "for us to go home early," "for them to arrive on time." Portuguese collapses this into a single inflected form: para irmos para casa cedo, para chegarem a tempo. Learning the personal infinitive often means unlearning the urge to add que and move to the subjunctive — English speakers, trained on Spanish, tend to reach for que every time.
Spanish speakers have the opposite problem. Spanish has no personal infinitive and uses que + subjunctive everywhere Portuguese allows the personal infinitive. A Spaniard learning Portuguese may produce grammatical sentences like es importante que lleguen temprano and never realise that the more idiomatic Portuguese is é importante chegarem cedo.
Common mistakes
❌ Queremos falarmos com o teu pai.
Same-subject clauses after volition verbs take the impersonal — no ending.
✅ Queremos falar com o teu pai.
We want to speak with your father.
❌ É importante eles chegam cedo.
After an impersonal expression with a different subject, you need the personal infinitive, not the indicative.
✅ É importante eles chegarem cedo.
It's important that they arrive early.
❌ Posso falarmos um minuto?
Modals like *poder* always take the impersonal infinitive, even with the nós-subject.
✅ Podemos falar um minuto?
Can we talk for a minute?
❌ Para eu compreender o texto, é preciso ler com atenção.
Not wrong, but awkward — when the subject appears explicitly, the personal form is clearer: *para eu compreender* is fine, but learners often leave out the pronoun *and* fail to inflect: ❌ *Para compreender, é preciso…* when they mean 'for me to understand.'
✅ Para compreenderes o texto, tens de o ler devagar.
For you to understand the text, you have to read it slowly.
❌ Antes de eles partirmos, quero falar com eles.
The inflection must match the *subject of the infinitive clause* — here *eles*, not *nós*.
✅ Antes de eles partirem, quero falar com eles.
Before they leave, I want to speak with them.
❌ Vi os miúdos brincar no parque.
With a lexical subject (*os miúdos*) after a perception verb, the personal infinitive is strongly preferred in PT-PT.
✅ Vi os miúdos brincarem no parque.
I saw the kids play in the park.
❌ É preciso estudarmos, disse ele.
If *he* said it to *them* (separate subject), match the inflection to the intended subject — here the subject is generic 'one/you,' which takes the impersonal.
✅ É preciso estudar, disse ele. / É preciso (tu) estudares, disse ele.
He said you need to study. (Choose based on intended subject.)
❌ Ele fez nós irmos embora.
Causative *fazer* + personal infinitive with lexical subject is fine, but the pronoun *nós* must still appear in its strong form as the subject — *fazer* does not take *nós* as an object here.
✅ Ele fez-nos ir embora. / Ele fez com que fôssemos embora.
He made us leave. (In PT-PT, causative *fazer* with a pronoun clitic takes the impersonal; with a lexical subject, the personal form reappears: *Ele fez os convidados irem embora.*)
Key takeaways
- The personal infinitive inflects for person and number: falar, falares, falar, falarmos, falarem. Even irregular verbs follow this pattern.
- Use the personal form when the infinitive has its own subject, after prepositions with an explicit subject, after perception/causative verbs with lexical subjects, and in impersonal-expression complements.
- Use the impersonal form when the subject is the same as the main verb, after modals (poder, dever, ter de), in fixed expressions, and for generic statements.
- The personal infinitive is often a more elegant alternative to que
- conjuntivo. PT-PT speech prefers it.
- English speakers tend to under-use the personal infinitive; Spanish speakers tend to avoid it entirely. Getting it right is one of the fastest ways to make your Portuguese sound native.
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: FormationB1 — How to build the infinitivo pessoal: take the infinitive and add the personal endings -es, -mos, -em. No stem changes, no irregularities — the only exception is pôr, which keeps its circumflex.
- Personal vs Regular Infinitive: When to InflectB1 — The decision rules for choosing between the impersonal (bare) infinitive and the personal (inflected) infinitive — the most consulted page in this set.
- 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 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 ErrorsB1 — How English speakers misuse the personal infinitive — over-inflecting, under-inflecting, and confusing it with the subjunctive.