In short

The gerund is the single invariable -ndo form: falando, comendo, partindo. The first thing to unlearn is the reflex that it means “-ing” as in English: in European Portuguese the gerund is not the everyday progressive - “I am eating” is estou a comer (estar a + infinitivo, Lesson 9), never estou comendo, which is Brazilian. What the EP gerund really does is compress a whole adverbial clause - cause, condition, time, manner - into one word, plus mark gradual change with ir and vir. Alongside it live three look-alike infinitive periphrases, estar para, ir a and vir a, that a B2 learner keeps confusing with the plain future.

The rule

Forming the gerund

Drop the -r of the infinitive and add -ndo. This is completely regular, even for verbs that are irregular everywhere else:

falar -> falando, comer -> comendo, partir -> partindo, pôr -> pondo, ter -> tendo, ser -> sendo, ir -> indo, vir -> vindo. The form never changes for person, gender or number - there is no falandos or falanda.

For an action completed before the main verb, use the compound gerund tendo + past participle: tendo falado, tendo comido, tendo posto.

What the gerund does (and does not do) in EP

It does not build the progressive. Compare:

• Estou a ler. = I am reading. (EP: estar a + infinitivo)
• Estou lendo. = Brazilian only.

Its real home is the reduced adverbial clause (a oração gerundiva): the gerund replaces a conjunction plus a finite verb, and the reader recovers the relationship from context.

• Cause: Estando cansado, ficou em casa. = Being tired, he stayed home. (= como estava cansado)
• Condition: Correndo, ainda apanhas o autocarro. = If you run, you’ll still catch the bus. (= se correres)
• Time / simultaneity: Voltando para casa, encontrei um amigo. = Going back home, I ran into a friend. (= quando voltava para casa)
• Manner: Saiu batendo com a porta. = He left slamming the door.
• Anteriority (compound): Tendo acabado o relatório, enviou-o. = Having finished the report, he sent it.

If the gerund clause has its own subject, state it right after the gerund and set the clause off with a comma: Estando o professor doente, a aula foi adiada.

In a bare gerund clause the clitic attaches to the gerund itself, hyphenated, exactly as on a bare infinitive (Lesson 30): Fechou o portão empurrando-o com o pé. Vestindo-se à pressa, saiu de casa. A negation in front of the clause pulls the pronoun forward instead (Não se sentindo bem, foi para casa.), and in the compound gerund it rides tendo, never the participle: tendo-me enganado, not tendo enganado-me.

Gradual change: ir and vir + gerund

Two periphrases with the gerund survive fully in EP because estar a + infinitivo cannot carry their meaning of gradual, cumulative change over time:

• ir + gerúndio - a process unfolding little by little: Vou percebendo cada vez mais. (I am gradually understanding more and more.)
• vir + gerúndio - “has been …-ing”, building up to now: A situação vem melhorando. (The situation has been improving.)

But with estar, ficar and andar, EP uses a + infinitivo, not the gerund: ficou a olhar (not ficou olhando), anda a estudar (not anda estudando).

The three companion periphrases: estar para, ir a, vir a

These use the infinitive, not the gerund, but they cluster here because they express the same kind of circumstance and are easy to mix up with the plain near future ir + infinitivo (Lesson 11):

• estar para + infinitivo - on the point of, about to (often with reluctance): O comboio está para chegar. (The train is about to arrive.) Não estou para brincadeiras. (I’m not in the mood for nonsense.)
• ir a + infinitivo - caught in the very act, “was just about to”: Ia a sair quando o telefone tocou. (I was just leaving when the phone rang.) Note the a: without it, ia sair would read as a past-in-the-future.
• vir a + infinitivo - to come to / eventually do: Veio a saber a verdade. (He eventually learned the truth.) Se vieres a precisar, diz. (If you should come to need it, say so.)

Forms & patterns

Forming the gerund (simple and compound):

Circumstantial values of the gerund clause:

Gerund and companion periphrases:

Examples

Common mistakes

• Estou comendo agora. -> Estou a comer agora. - EP builds the progressive with estar a + infinitivo; estar + gerund is Brazilian.
• Ele ficou olhando para mim. -> Ele ficou a olhar para mim. - with ficar, estar and andar, EP takes a + infinitivo, never the gerund.
• Vou a comprar pão (as a plan) -> Vou comprar pão - the near future is ir + infinitive with no a; ir a + infinitive means “in the very act of”.
• Ia saindo quando… (meaning “I was just leaving”) -> Ia a sair quando… - the “caught in the act” reading needs ir a + infinitivo; bare ia + gerund reads as Brazilian.
• Estando doente a aula foi adiada. -> Estando o professor doente, a aula foi adiada. - when the gerund clause has its own subject, name it and mark the clause with a comma.
• Ela partiu deixando a porta aberto. -> … a porta aberta - only the gerund is frozen; words it governs still agree (porta is feminine).
• Duas pessoas comendos -> comendo - the gerund never takes a plural or feminine ending; it is one fixed form.

Tips

• Build any gerund the same way - infinitive minus -r plus -ndo - even for irregular verbs (pôr -> pondo, ter -> tendo, vir -> vindo). It is invariable.
• Reach for the gerund mainly in reduced adverbial clauses; it compresses “como / se / quando + finite verb” into one word and reads well in writing.
• Keep the plain “what I’m doing now” as estar a + infinitivo (Lesson 9); save the gerund for circumstance, not for the ordinary progressive.
• EP still uses ir + gerúndio and vir + gerúndio for gradual change (vou percebendo, vem aumentando), but estar / ficar / andar take a + infinitivo.
• Separate the three look-alikes: ir + infinitivo = near future; ir a + infinitivo = caught in the act; a + infinitivo = plain ongoing action.
• In Brazil: the gerund is the normal progressive (estou comendo, ficou olhando) and gerund periphrases are far more frequent, so Brazilian text shows many -ndo forms where EP writes a + infinitivo.