Spanish si clauses: how to build conditional sentences

A Spanish conditional sentence has two halves: a si (if) clause that states a condition, and a result clause that says what happens. The tenses you pick tell the listener how real you think the condition is. There are three main patterns, from a likely condition to an impossible one:

The single rule that saves the most mistakes: after si meaning “if”, you never use the present subjunctive and never use the plain conditional. Match the pattern instead.

Type si-clause Result Example
Real present indicative present / future / command Si llueve, me quedo en casa.If it rains, I stay home.
Hypothetical imperfect subjunctive conditional Si tuviera dinero, viajaría.If I had money, I would travel.
Impossible past pluperfect subjunctive conditional perfect Si hubiera estudiado, habría aprobado.If I had studied, I would have passed.

Real conditions: si + present

Use this pattern when the condition is genuinely possible or likely. The si clause stays in the present indicative, and the result can be present, future or a command.

Si estudias, apruebas el examen.
If you study, you pass the exam.

Si tienes tiempo, te llamo esta noche.
If you have time, I’ll call you tonight.

Si vas al mercado, compra pan.
If you go to the market, buy bread.

Notice that Spanish uses the present after si even when the result looks to the future. English does the same thing (“If it rains, I will stay”) — the if half stays present in both languages.

One quick contrast: do not confuse si (if) with cuando (when). Si marks a condition that may or may not happen, while cuando about the future triggers the subjunctive: Si llueve, me quedo (if it rains) but Cuando llueva, me quedaré (when it rains). Only the cuando sentence uses the subjunctive here.

Hypothetical conditions: si + imperfect subjunctive

When the condition is unlikely, imaginary or contrary to the present facts, move the si clause into the imperfect subjunctive and put the result in the conditional. This is the “if I were you / if I had money” situation.

Si tuviera más tiempo, aprendería a cocinar.
If I had more time, I would learn to cook.

Si fuera rico, viajaría por todo el mundo.
If I were rich, I would travel all over the world.

Yo que tú, no diría nada.
If I were you, I wouldn’t say anything.

The imperfect subjunctive is the form that ends in -ara/-iera (or the equally correct -ase/-iese): hablara, tuviera, fuera, pudiera. If you can build that form, this whole pattern falls into place.

Impossible past: si + pluperfect subjunctive

To talk about a past that did not happen — a regret or a missed chance — use the pluperfect subjunctive (hubiera + past participle) in the si clause and the conditional perfect (habría + past participle) in the result.

Si hubiera salido antes, no habría perdido el tren.
If I had left earlier, I wouldn’t have missed the train.

Si me lo hubieras dicho, te habría ayudado.
If you had told me, I would have helped you.

This pattern always describes something that is now fixed and cannot change, so it naturally carries a note of regret or reproach.

The rule after si

The trap for English speakers is to translate “would” as the conditional and drop it straight after si. In Spanish the conditional and the present subjunctive are both banned in the si clause itself. This pattern often overlaps with the Spanish subjunctive triggers, but si is not one of the triggers that takes the present subjunctive.

Si tendría dinero, viajaría. → Si tuviera dinero, viajaría.
If I had money, I would travel.

Common mistakes

Using the conditional after si

A conditional such as tendría cannot follow si. Use the imperfect subjunctive.

Si podría, iría contigo. → Si pudiera, iría contigo.
If I could, I would go with you.

Using the present subjunctive after si

Spanish does not use the present subjunctive in an if clause. A real condition keeps the present indicative.

Si tengas tiempo, llámame. → Si tienes tiempo, llámame.
If you have time, call me.

Keeping the result in the present

In a hypothetical sentence the result must move to the conditional, not stay present.

Si tuviera dinero, viajo. → Si tuviera dinero, viajaría.
If I had money, I would travel.

Conditionals are really about matching two halves of a sentence, which is exactly the kind of pattern that sticks through repetition. Fluera drills the si + result pairings in short sentences with instant feedback, so you can practice Spanish by reading the condition first and choosing the form that fits it.

Practice

Which form after si?

Question 1 of 13

Si ___ dinero, viajaría por todo el mundo. (hypothetical)

Frequently asked questions

What are the three types of si clauses in Spanish?
Real (si + present indicative, result in present/future/command: Si llueve, me quedo), hypothetical (si + imperfect subjunctive, result in the conditional: Si tuviera dinero, viajaría), and impossible past (si + pluperfect subjunctive, result in the conditional perfect: Si hubiera estudiado, habría aprobado).
Can you use the conditional after si in Spanish?
No. After si meaning "if", Spanish never uses the conditional or the present subjunctive. Say Si tuviera tiempo (not Si tendría tiempo) for a hypothetical condition.
What tense follows si for a real, likely condition?
The present indicative: Si estudias, apruebas. The result clause can be present, future or a command, but the si clause stays in the present.
How do I say "if I were you" in Spanish?
Use Si fuera tú or the very common Yo que tú plus the conditional: Yo que tú, no diría nada (If I were you, I wouldn't say anything).
Does the si clause always come first?
No. You can put either half first. Si tuviera dinero, viajaría and Viajaría si tuviera dinero mean the same thing; only add a comma when the si clause comes first.
What are the -ase and -iese forms like tuviese and fuese?
They are an alternative spelling of the imperfect subjunctive. Si tuviera and si tuviese are equally correct and interchangeable; the -ara/-iera forms are more common in everyday speech, while -ase/-iese shows up more in writing.