Estar (to be) · All tenses

Use estar for temporary states (estoy cansado — I am tired), location (estoy en casa — I am at home), and ongoing actions with the gerund (estoy comiendo — I am eating). Use ser for permanent identity, origin, profession, and time.

Estoy comes from an older form 'estó' plus the archaic personal ending '-y' (also seen in soy, doy, voy). The '-y' marked first-person singular in earlier Spanish and was retained on these high-frequency verbs while it disappeared elsewhere.

The preterite of estar uses the irregular stem 'estuv-': yo estuve, tú estuviste, él/ella/usted estuvo, nosotros/as estuvimos, vosotros/as estuvisteis, ellos/ellas/ustedes estuvieron. Note there are no accent marks on these forms — that's a key visual cue.

Use 'estuve' (preterite) when the state had a clear beginning and end: 'Estuve en París tres días' (I was in Paris for three days — bounded). Use 'estaba' (imperfect) for ongoing, background, or repeated past states: 'Estaba cansado cuando llegué' (I was tired when I arrived — describing a state at a moment).

Estar inherits the irregular preterite stem 'estuv-' from Latin 'stetui' (perfect of stare). This irregular stem shows up only in the preterite and tenses derived from it (like the imperfect subjunctive 'estuviera/estuviese'). It's one of about 15 'pretérito grave' verbs in Spanish.

Estar in the imperfect is regular: yo estaba, tú estabas, él/ella/usted estaba, nosotros/as estábamos, vosotros/as estabais, ellos/ellas/ustedes estaban. The yo and él/ella/usted forms are identical — this is normal for the imperfect of -ar verbs.

Use 'estaba' for ongoing or background past states: descriptions, mental and physical conditions at a moment, or repeated/habitual past situations. 'Estaba feliz' (I was happy — at that time, background). 'Estuve feliz' (I was happy — a specific moment that ended). The imperfect is the workhorse for description, the preterite for events.

Spanish -ar verb imperfect endings collapse the first-person singular (yo) and third-person singular (él/ella/usted) into a single -aba form. Context — usually a pronoun, name, or surrounding subject — disambiguates. This is true for all regular -ar verbs in the imperfect.

The present subjunctive of estar is: yo esté, tú estés, él/ella/usted esté, nosotros/as estemos, vosotros/as estéis, ellos/ellas/ustedes estén. Note the accent marks on every form except nosotros and vosotros — they mark the stressed syllable.

Use it in 'que' clauses after triggers of doubt, emotion, wish, command, or impersonal expressions: 'Espero que estés feliz', 'Es necesario que esté presente', 'Quiero que estemos solos'. Also after 'cuando', 'aunque', and similar conjunctions when referring to future or hypothetical situations.

The yo, tú, él/ella/usted, and ellos/ellas/ustedes forms (esté, estés, esté, estén) are stressed on the final syllable, which Spanish marks with an accent when the word ends in a vowel, n, or s and would otherwise be stressed on the second-to-last syllable. Nosotros (estemos) and vosotros (estéis) follow regular stress rules without an accent.

Estar in the future is regular: yo estaré, tú estarás, él/ella/usted estará, nosotros/as estaremos, vosotros/as estaréis, ellos/ellas/ustedes estarán. The stem is the full infinitive 'estar-' — no shortening, unlike irregular futures (tener → tendré).

Both are correct and widely used. 'Voy a estar' (I am going to be) feels more conversational and immediate; 'estaré' (I will be) feels more formal or removed in time. In daily speech, 'voy a estar' is more common for near-future plans; 'estaré' is common in writing and formal speech, and also for conjecture: '¿Dónde estará Juan?' = 'Where could Juan be?'

Spanish future endings (-é, -ás, -á, -emos, -éis, -án) carry accent marks to preserve their stressed pronunciation on the final syllable. This is universal across all Spanish verbs in the future tense, regardless of whether the verb is regular or irregular.