si
/si/
The English word "whether" can be translated into Spanish as si.
Meaning: if, whether or not (conj)
Which one should you use?
The formal phrase ya sea que can be used specifically to introduce a choice or an alternative.
How does it change in a sentence?
To express the concept of "whether or not" in a sentence, you can use si… o no or simply use si followed by the alternative.
How do you pronounce it?
/si/
What mistakes should you avoid?
Be careful not to confuse the conjunction si with the adverb sí, which means "yes" and requires a written accent.
Did you know?
- The word si originates from the Proto-Indo-European root *sóder, which is the same ancient ancestor that gave rise to the English word 'so'.
- In some legal or archaic Spanish texts, you might see si bien used not just as 'if' but to mean 'although', shifting the meaning from a condition to a concession.
- While si usually introduces a condition, when it is used as 'whether' in indirect questions, it often triggers the subjunctive mood in the following verb to emphasize uncertainty.
Examples in context
- No sé si viene o no.I don't know whether he comes or not.This sentence is useful for showing how to use si to express "whether… or not".Tatoeba #1020826 by Shishir, translation #284285 by Zifre
- No saben si vendrán.They don't know whether they'll come.This sentence demonstrates using si to express uncertainty about a future action.Tatoeba #7842052 by arh, translation #9179716 by DJ_Saidez
- No sé si vendrá o no.I don't know whether he will come or not.This sentence shows the use of si in a "whether… or not" structure with a future tense.Tatoeba #898448 by Shishir, translation #284295 by CK
- No estoy seguro si iré a la fiesta.I'm not sure whether I will go to the party.
- Voy a esperar ya sea que llueva o no.I'm going to wait, whether it rains or not.
- No sé si vendrás a la fiesta, o qué.I don't know whether you'll come to the party, or what.
- ¿Sabes si va a llover mañana, o acaso saldrá el sol?Do you know whether it's going to rain tomorrow, or if the sun will come out?
- No importa si llueve o hace sol, disfrutaremos del viaje.It doesn't matter whether it rains or the sun shines, we'll enjoy the trip.
- ¿Podrías decirme si vas a la reunión mañana?Could you tell me whether you're going to the meeting tomorrow?
- No sé si podré acompañarte al concierto.I don't know whether I'll be able to join you at the concert.
- 251 more sentences on Tatoeba
Example conversation
Daniel and María are talking about their plans for the weekend.
- Daniel¿Sabes si lloverá mañana?Do you know if it will rain tomorrow?
- MaríaNo estoy segura de si lloverá.I am not sure whether it will rain.
- DanielBueno, yo no sé si ir al parque.Well, I don't know whether to go to the park.
- MaríaSi hace sol, deberías ir.If it is sunny, you should go.
Sources
- Wiktionary, “whether” translations and entries si, CC BY-SA 4.0, dump of 2026-09-26.
- Word origins: Wiktionary entries si, CC BY-SA 4.0.
- Example sentences: Tatoeba CC BY 2.0 FR.
