Decidir (To Decide) — Full Conjugation

Decidir means to decide — to make up your mind, to settle a question, to come down on one side of a choice. It appears in everything from já decidi (I've decided) to decidiu-se pela praia (he went with the beach). Grammatically, decidir is a textbook example of a fully regular third-conjugation (-ir) verb: every stem, every ending, every tense follows the standard pattern. There are no stem changes, no spelling shifts, no irregular participles. If you know the regular -ir template, you know decidir.

What deserves attention is not the conjugation but the syntax around it: which preposition does it take? Does it require the subjunctive in subordinate clauses? When does it go reflexive? These choices are what separate a learner who can conjugate decidir from one who uses it like a native speaker.

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Present indicative — presente do indicativo

Use this tense for current actions and habitual behavior. Eu decido depressa = I decide quickly.

Imperfect indicative — pretérito imperfeito

Past habits, background, ongoing past action. Decidia tudo sozinha = she decided everything on her own (habitually).

Preterite indicative — pretérito perfeito simples

Completed past actions — this is the tense you will use most often with decidir, because deciding is typically a moment, not a process.

Note: the nós form decidimos is identical in the present and preterite — this is a feature of all regular -ir verbs. Agora decidimos (now we decide) vs ontem decidimos (yesterday we decided). Context disambiguates.

Pluperfect indicative, simple — pretérito mais-que-perfeito simples

Literary synthetic pluperfect. In speech, use the compound form below.

The third-person plural decidiram is identical to the preterite; context disambiguates.

Pluperfect indicative, compound — pretérito mais-que-perfeito composto

The everyday had decided. Imperfect of ter plus decidido.

Present perfect — pretérito perfeito composto

Action repeated or ongoing up to now — not the English present perfect. Tens decidido tudo sem me consultares = you've been deciding everything without consulting me (recent, recurring).

Simple future — futuro do indicativo simples

Formal / written future. Everyday speech overwhelmingly prefers vou decidir, vais decidir.

Future perfect — futuro perfeito

Will have decided. Future of ter plus decidido.

Conditional — condicional

Decidiria agora, mas falta-me informação = I would decide now, but I lack information.

Conditional perfect — condicional composto

Would have decided.

Present subjunctive — presente do conjuntivo

Built from the eu form decido → drop -o → add -a, -as, -a, -amos, -ais, -am.

Imperfect subjunctive — imperfeito do conjuntivo

Se decidisses sair, avisa-me = if you were to decide to leave, let me know.

Future subjunctive — futuro do conjuntivo

A living tense in Portuguese. Quando decidires, diz-me = when you decide, tell me.

Present perfect subjunctive — pretérito perfeito do conjuntivo

Espero que já tenhas decidido = I hope you've already decided.

Pluperfect subjunctive — pretérito mais-que-perfeito do conjuntivo

Se tivesse decidido antes, teria evitado o problema = if I had decided earlier, I would have avoided the problem.

Future perfect subjunctive — futuro perfeito do conjuntivo

Imperative — imperativo

Affirmative:

Negative:

Decide tu = you decide (tu); decide-te! = make up your mind! (with reflexive pronoun attached).

Personal infinitive — infinitivo pessoal

Identical in form to the future subjunctive.

Usage notes — the prepositions that matter

Which preposition follows decidir carries a real meaning difference. Learn these patterns as a block.

decidir + infinitive — to decide to do X

Direct infinitive, no preposition. This is the most common pattern.

decidir que + indicative — to decide that X (factual outcome)

Decidir que takes the indicative — because the content of the decision is presented as a fact that will hold. This is a common point of confusion with English-speaking learners who expect something like the subjunctive.

decidir-se (reflexive) — to make up one's mind

Reflexive form emphasizes the internal process, not just the outcome. Strongly implies hesitation beforehand.

Note: decidir-se a + infinitive is the most common reflexive pattern. The a is required here.

decidir-se por — to settle on, to go with

When choosing between options and landing on one.

decidir sobre + topic — to decide about / on (an issue)

Formal, common in legal and bureaucratic registers.

Related vocabulary

• decisão (f.) — decision
• decisivo / decisiva — decisive
• decidido / decidida — decisive (as personality trait), determined
• indeciso / indecisa — indecisive
• decisor / decisora — decision-maker (administrative/formal)

Example sentences in context

Common mistakes

Key takeaways

• Decidir is a completely regular -ir verb. No stem changes, no spelling shifts, no irregular participle.
• Use it as your mental template when you forget the regular -ir pattern for any other verb.
• Decidir + infinitive (no preposition) is the most common pattern: decidi sair.
• Decidir-se a + infinitive emphasizes the internal resolution: decidiu-se a falar.
• Decidir-se por + object means to settle on a choice: decidiu-se pelo azul.
• Decidir que + indicative introduces a factual decided outcome — no subjunctive here. This is a frequent English-speaker error.
• The nós form decidimos is identical in present and preterite, as in every regular -ir verb.
• Related words: decisão, decidido, indeciso, decisivo.