Talvez vs. se calhar
While both talvez and se calhar translate to "maybe" or "perhaps," distinguishing them is crucial for sounding natural. The main differences lie in geographical usage (Brazil vs. Portugal) and the grammatical mood required (Subjunctive vs. Indicative).
Talvez
A2This word is used universally in both Brazilian and European Portuguese to express broad uncertainty. Its defining grammatical feature is that it almost always requires the following verb to be in the Subjunctive mood, which expresses doubt or hypothetical situations.
Talvez ela esteja em casa agora.
(Perhaps she is at home right now.)
Talvez nós possamos ajudar você amanhã.
(Maybe we can help you tomorrow.)
Não compre isso agora, talvez seja muito caro.
(Don't buy that now, maybe it is too expensive.)
Talvez chova mais tarde, leve o guarda-chuva.
(Perhaps it will rain later, take the umbrella.)
Se calhar
B1This expression is very common in European Portuguese (Portugal) but rarely understood as "maybe" in Brazil. It generally implies "it's probable that." Grammatically, it is easier for learners because it is followed by the Indicative mood (the standard verb form used for facts).
Se calhar ela está em casa agora.
(Maybe she is at home right now.)
Se calhar vamos ao cinema hoje à noite.
(Maybe we are going to the cinema tonight.)
O trânsito está horrível, se calhar chegamos atrasados.
(The traffic is terrible, chances are we will arrive late.)
Se calhar é melhor ficarmos aqui.
(Maybe it is better if we stay here.)
Summary
Use talvez followed by the Subjunctive mood in formal contexts or anywhere in the Portuguese-speaking world. Use se calhar followed by the Indicative mood primarily for casual conversation in Portugal.