O futuro — duas maneiras
Portuguese has two main ways to talk about the future. The everyday spoken form is ir + infinitive (just like English 'going to'): Vou comer agora = I'm going to eat now. The simple future tense futuro do presente (falarei, comerei, partirei) is reserved for written, formal, or emphatic contexts. If you're chatting, use ir + infinitive. If you're writing a news article or a wedding vow, use the -rei forms.
ir + infinitive — the everyday future
Conjugate ir in the present, then add the bare infinitive of the action verb. eu vou comer, tu vais comer, ele/ela vai comer, nós vamos comer, eles/elas vão comer. Vou ligar-te amanhã = I'll call you tomorrow. Vamos viajar para Lisboa = We're going to travel to Lisbon. This is what you'll hear and say 90% of the time. Same construction in PT and BR. With ir itself, you can say either vou ir (sounds redundant) or just vou + place: Vou ao Porto amanhã = I'm going to Porto tomorrow.
Futuro do presente — the formal future
Take the full infinitive and add -ei, -ás, -á, -emos, -ão. falar → falarei, falarás, falará, falaremos, falarão. Same endings on every regular verb regardless of family: comer → comerei, comerás…; partir → partirei, partirás… Notice the accents: falarás, falará, falarão — they signal stress on the ending. Falaremos has stress on the e, no accent needed.
The three irregulars
Only three verbs are irregular in the futuro do presente, and they're all stem-shrinkers. dizer → direi, dirás, dirá, diremos, dirão (the -ze- drops out). fazer → farei, farás, fará, faremos, farão. trazer → trarei, trarás, trará, traremos, trarão. Endings stay the same as the regulars; only the stem is shortened. Everything else — ser, ter, ir, estar — is regular: serei, terei, irei, estarei.
When to choose which
Spoken / casual: ir + infinitivo. Amanhã vou trabalhar até tarde. Written / formal / news: futuro do presente. O presidente falará amanhã às oito. Predictions and probability often take the simple future: Serão dez horas = It must be ten o'clock (probability, not future time!). For weather forecasts and headlines: Choverá no fim de semana = It will rain this weekend. In dialogue, swapping in falarei for vou falar sounds bookish. Stick to the everyday form unless you're being formal.
Time markers for the future
amanhã = tomorrow. depois de amanhã = the day after tomorrow. na próxima semana = next week. no próximo mês = next month. no próximo ano / para o ano = next year (PT often says para o ano in casual speech). logo = soon / later today. mais tarde = later. daqui a + time = in (period from now): daqui a dois dias = in two days. Vou ver-te logo = I'll see you later. Falaremos na próxima semana = We'll talk next week.
Negation and questions
Negate by putting não before the conjugated verb: Não vou comer / Não comerei. Questions are intonation only: Vais sair? = Are you going to go out? Comerás connosco? = Will you eat with us? — formal/literary. The contraction connosco (PT) / conosco (BR) means 'with us' and shows up here naturally.
