Reale Bedingungssätze: si + Präsens

For everyday, possible conditions - if it rains, if I pass, if you get there first - Spanish uses a structure that English speakers will find familiar: si + present indicative, with a present, future, ir a or command in the other half.

The present in the result is very common where English prefers "will": Si tengo tiempo, te llamo - "If I have time, I'll call you."

No future after si

English already avoids "if I will have time", and Spanish follows the same rule even more strictly: in a real condition, the future and the conditional do not go after si. Si tengo tiempo, not *si tendré tiempo; si puedes, not *si podrás. Speakers of languages that do put a future here often transfer it, and examiners notice.

Two different kinds of si

The conditional si ("if") is not the same as the si of an indirect question, which means "whether". That second one does take a future: No sé si vendrá - "I don't know whether she'll come". Me pregunto si lloverá mañana. Test it in English: if "whether" fits, the future is fine.

And do not confuse si (if) with sí (yes), which carries an accent.

Order and punctuation

The two halves can swap. When the si clause comes first, a comma separates them; when it comes second, the comma usually goes: No vamos a la playa si llueve.

What you will hear in the street

• Como + subjunctive, as a warning or threat: Como llegues tarde otra vez, nos vamos sin ti. - "If you're late one more time, we're leaving without you."
• Por si acaso, "just in case": Coge el paraguas, por si acaso. And por si + present: Te dejo mi número por si te pierdes.
• Si no, "otherwise": Date prisa; si no, perdemos el tren.

Unlikely or imaginary conditions ("If I won the lottery...") use another structure, with the imperfect subjunctive, which comes at B1.