Si clauses are conditional sentences. They talk about what happens if something else happens. In Spanish, the word siif introduces the condition, and another clause gives the result.
Need a quick refresher on the present tense used after si? Review A1 present tense (-ar verbs).
Think of them in four friendly patterns. Learn the pattern, then plug in your verbs.
At a glance cheat sheet
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General truths and routines Si + presente, presente Si calientas hielo, se derrite.
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Real and likely future Si + presente, futuro / imperativo / presente Si llegas temprano, te invitaré. Si lo ves, dile.
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Hypothetical now or future Si + imperfecto de subjuntivo, condicional simple Si tuviera tiempo, estudiaría más.
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Hypothetical in the past Si + pluscuamperfecto de subjuntivo, condicional compuesto Si hubiera sabido, habría ido. Mixed time: Si hubiera estudiado, tendría un mejor trabajo.
Golden rule
Never use the future tense directly after siif. Use the present in the cláusula siif clause, then future in the result.
Drag the handle to compare
0) Si + presente, presente for facts and routines
Use this for general truths, normal results, and routines.
- Si calientas hielo, se derrite.
- Si mezclas azul y amarillo, sale verde.
- Si tengo hambre, picoteoI snack algo.
Why it works: the cause and the result are both presented as regular facts.
1) Si + presente, futuro or imperativo for likely results
Use this when the condition is real or likely. The result can be future, imperative, or even present in informal speech.
- Si llegas temprano, te invitaré a almorzar.
- Si ves a Ana, dile que me escriba. (imperative in the result)
- Si hace sol mañana, vamos a la playa. (present result, also fine)
Mini tip: You can swap the order.
- Te llamaré si tengo tiempo. No comma needed here.
Brush up on forms used in this pattern: review the simple future and affirmative commands (imperative).
2) Si + imperfecto de subjuntivo, condicional simple for hypotheticals
This is your go-to for unreal or less likely situations in the present or future.
- Si tuviera más tiempo, estudiaría italiano.
- Si fueras yo, no lo harías.
- Si lloviera hoy, nos quedaríamos en casa.
How to form the imperfect subjunctive fast:
- Take the preterite third-person plural, drop the -ron, add -ra endings.
- tuvieron → tuviera, tuvieras, tuviera, tuviéramos, tuvieran
- hicieron → hiciera, hicieras, hiciera, hiciéramos, hicieran
Two endings, same meaning
Hubiera and hubiese are both correct. Tuviera and tuviese are both correct. Use the -ra forms for simplicity.
New to these forms? Study the imperfect subjunctive and the matching conditional tense.
3) Si + pluscuamperfecto de subjuntivo, condicional compuesto for past unreal
Talk about something that did not happen in the past and its imagined result.
- Si hubiera sabido la respuesta, habría levantado la mano.
- Si hubiéramos salido antes, no habríamos llegado tarde.
- Mixed time result now: Si hubiera ahorrado más, tendría menos estrés hoy.
Formation refresher:
- Pluscuamperfecto de subjuntivo: hubiera/hubiese + participio
- Condicional compuesto: habría + participio
Arrange the words to form a correct sentence:
For forms and timelines, see the future perfect and conditional perfect and our overview of the pluperfect subjunctive in si clauses.
Punctuation and word order
- If the si clause comes first, add a comma after it.
- Si estudias, aprobarás.
- If the si clause comes second, no comma.
- Aprobarás si estudias.
Beware the accent
síyes with accent means yes. siif without accent means if. Do not mix them.
Quick practice
Which sentence is correct for a likely future situation?
Try saying these out loud:
- Si tengo tiempo esta tarde, …
- Si ganara la lotería, …
- Si hubiéramos salido a las ocho, …
Practice these patterns in context with our graded Spanish stories.
Extra notes and common pitfalls
- Do not use future after si
- Wrong: Si tendrás tiempo, llámame.
- Right: Si tienes tiempo, llámame.
- Imperfect in the past for habits
- Si llovía, nos quedábamos en casa. (used to do in the past)
- Advanced and regional
- You may hear imperfect for counterfactuals in some regions. Stick to the standard patterns above while learning.
If you need a refresher on habitual past forms, revisit the imperfect tense (regular verbs).
Upgrade your verbs fast
Keep a short list of high‑frequency verbs in the subjunctive and conditional, like tener, poder, ir, ser, hacer. Mix them into your si clauses for instant fluency.
Quick reference recap
- Zero conditional: Si + presente, presente
- First conditional: Si + presente, futuro or imperativo
- Second conditional: Si + imperfecto de subjuntivo, condicional simple
- Third conditional: Si + pluscuamperfecto de subjuntivo, condicional compuesto
- Mixed conditional: Past condition with present result
- Si hubiera estudiado, tendría un mejor trabajo.
Want more depth and variations? Read our B2 guide on si clauses.
Final takeaway
Master the four patterns, avoid future after si, and practice with verbs you already know. Soon you will build natural Spanish conditionals without thinking.