Alertar Conjugation in Spanish
The Spanish verb alertar means to alert, and it is a verb you will use again and again once you know it. Alertar means to alert, to warn someone about a danger so they can act in time. It is used for weather, health, security and emergencies, and it is fully regular. Like every Spanish verb, alertar changes its ending for each person and tense, and this page gives you the complete picture: every tense, every person, the gerund and the past participle, all from the verified conjugation tables. For example, in the present tense you say alerto a la población del peligro, and in the preterite you say alerté a la policía del robo. Work through the tables below, read the notes for each tense, and then test yourself with the examples, the common mistakes and the quiz at the end of the page.
Quick facts
- Infinitive: alertar
- English: to alert
- Verb type: regular -ar verb
- Ending: -ar
- Gerund: alertando
- Past participle: alertado
- Auxiliary verb: haber (all perfect tenses are formed with haber + alertado)
Pronunciation is not listed on this page: the verified tables do not include IPA for alertar, so no pronunciation is given rather than an invented one. Alertar is fully regular: alerto, alerta. It warns of a danger; avisar is the general word for telling someone something.
Full conjugation tables
Every form below comes from the verified conjugation tables for alertar. The imperfect subjunctive is shown in its -ra forms; the -se forms use the same stem. For reflexive verbs, the pronoun column shows the reflexive pronoun that goes before each form.
Present indicative
| Person | Form |
|---|---|
| yo | alerto |
| tú | alertas |
| él/ella/Ud. | alerta |
| nosotros/as | alertamos |
| vosotros/as | alertáis |
| ellos/ellas/Uds. | alertan |
Preterite
| Person | Form |
|---|---|
| yo | alerté |
| tú | alertaste |
| él/ella/Ud. | alertó |
| nosotros/as | alertamos |
| vosotros/as | alertasteis |
| ellos/ellas/Uds. | alertaron |
Imperfect
| Person | Form |
|---|---|
| yo | alertaba |
| tú | alertabas |
| él/ella/Ud. | alertaba |
| nosotros/as | alertábamos |
| vosotros/as | alertabais |
| ellos/ellas/Uds. | alertaban |
Future
| Person | Form |
|---|---|
| yo | alertaré |
| tú | alertarás |
| él/ella/Ud. | alertará |
| nosotros/as | alertaremos |
| vosotros/as | alertaréis |
| ellos/ellas/Uds. | alertarán |
Conditional
| Person | Form |
|---|---|
| yo | alertaría |
| tú | alertarías |
| él/ella/Ud. | alertaría |
| nosotros/as | alertaríamos |
| vosotros/as | alertaríais |
| ellos/ellas/Uds. | alertarían |
Present perfect
| Person | Form |
|---|---|
| yo | he alertado |
| tú | has alertado |
| él/ella/Ud. | ha alertado |
| nosotros/as | hemos alertado |
| vosotros/as | habéis alertado |
| ellos/ellas/Uds. | han alertado |
Pluperfect
| Person | Form |
|---|---|
| yo | había alertado |
| tú | habías alertado |
| él/ella/Ud. | había alertado |
| nosotros/as | habíamos alertado |
| vosotros/as | habíais alertado |
| ellos/ellas/Uds. | habían alertado |
Future perfect
| Person | Form |
|---|---|
| yo | habré alertado |
| tú | habrás alertado |
| él/ella/Ud. | habrá alertado |
| nosotros/as | habremos alertado |
| vosotros/as | habréis alertado |
| ellos/ellas/Uds. | habrán alertado |
Conditional perfect
| Person | Form |
|---|---|
| yo | habría alertado |
| tú | habrías alertado |
| él/ella/Ud. | habría alertado |
| nosotros/as | habríamos alertado |
| vosotros/as | habríais alertado |
| ellos/ellas/Uds. | habrían alertado |
Present subjunctive
| Person | Form |
|---|---|
| yo | alerte |
| tú | alertes |
| él/ella/Ud. | alerte |
| nosotros/as | alertemos |
| vosotros/as | alertéis |
| ellos/ellas/Uds. | alerten |
Imperfect subjunctive (-ra)
| Person | Form |
|---|---|
| yo | alertara |
| tú | alertaras |
| él/ella/Ud. | alertara |
| nosotros/as | alertáramos |
| vosotros/as | alertarais |
| ellos/ellas/Uds. | alertaran |
Imperative (affirmative)
| Person | Form |
|---|---|
| tú | alerta |
| él/ella/Ud. | alerte |
| nosotros/as | alertemos |
| vosotros/as | alertad |
| ellos/ellas/Uds. | alerten |
Imperative (negative)
| Person | Form |
|---|---|
| tú | alertes |
| él/ella/Ud. | alerte |
| nosotros/as | alertemos |
| vosotros/as | alertéis |
| ellos/ellas/Uds. | alerten |
Gerund and past participle
| Form | Spanish | Use |
|---|---|---|
| Gerund | alertando | with estar for the progressive: estoy alertando |
| Past participle | alertado | with haber for the perfect tenses: he alertado |
How to use each tense
Present indicative
Use the present for routines, general facts and what is happening right now. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For alertar, the present looks like this in a real sentence: Alerto a la población del peligro. Learn the present forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Preterite
Use the preterite for finished actions with a clear end, often with ayer, el año pasado or anoche. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For alertar, the preterite looks like this in a real sentence: Ayer, alerté a los vecinos del incendio. Learn the preterite forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Imperfect
Use the imperfect for background, habits and actions in progress in the past, often with de niño, antes or mientras. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For alertar, the imperfect looks like this in a real sentence: De niño, alertaba a la policía del robo. Learn the imperfect forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Future
Use the future for plans, predictions and promises, often with mañana, el año que viene or pronto. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For alertar, the future looks like this in a real sentence: Mañana, alertaré sobre la tormenta que viene. Learn the future forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Conditional
Use the conditional for polite requests, hypotheticals and what would happen, often with si clauses. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For alertar, the conditional looks like this in a real sentence: Alertaría a la población del peligro si pudiera. Learn the conditional forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Present perfect
Use the present perfect for recent actions and experiences, often with hoy, esta semana or ya. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For alertar, the present perfect looks like this in a real sentence: Hoy, he alertado a los vecinos del incendio. Learn the present perfect forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Pluperfect
Use the pluperfect when one past action happened before another past action. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For alertar, the pluperfect looks like this in a real sentence: Había alertado a la policía del robo antes de salir. Learn the pluperfect forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Future perfect
Use the future perfect for something that will already be finished by a future time. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For alertar, the future perfect looks like this in a real sentence: Para mañana, habré alertado sobre la tormenta que viene. Learn the future perfect forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Conditional perfect
Use the conditional perfect for what would have happened under different conditions. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For alertar, the conditional perfect looks like this in a real sentence: Habría alertado a la población del peligro con más tiempo. Learn the conditional perfect forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Present subjunctive
Use the present subjunctive after expressions of wish, doubt, emotion and hope, such as espero que or quiero que. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For alertar, the present subjunctive looks like this in a real sentence: Espero que él alerte a los vecinos del incendio. Learn the present subjunctive forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Imperfect subjunctive (-ra)
Use the imperfect subjunctive after past wishes and in si clauses about the past, and note the -ra forms shown here; the -se forms use the same stem. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For alertar, the imperfect subjunctive looks like this in a real sentence: Si él alertara a la policía del robo, todo cambiaría. Learn the imperfect subjunctive forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Imperative (affirmative)
Use the affirmative imperative for direct commands, instructions and invitations. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For alertar, the affirmative imperative looks like this in a real sentence: ¡Alerta sobre la tormenta que viene! Learn the affirmative imperative forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Imperative (negative)
Use the negative imperative, always with no, to tell someone not to do something. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For alertar, the negative imperative looks like this in a real sentence: No alertes a la población del peligro. Learn the negative imperative forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Example sentences
Ten natural sentences with alertar, covering different tenses and persons. Each one uses a form from the tables above.
- Alerto a la población del peligro. — I alert the population of the danger.
- Alerta a los vecinos del incendio. — He/she alerts the neighbours about the fire.
- Ayer, alerté a la policía del robo. — Yesterday, I alerted the police about the robbery.
- Antes, nosotros alertábamos sobre la tormenta que viene. — Before, we used to alert about the coming storm.
- Mañana, tú alertarás a la población del peligro. — Tomorrow, you will alert the population of the danger.
- Yo alertaría a los vecinos del incendio si tuviera más tiempo. — I would alert the neighbours about the fire if I had more time.
- Él ha alertado a la policía del robo. — He has alerted the police about the robbery.
- Espero que él alerte sobre la tormenta que viene. — I hope he alerts about the coming storm.
- Yo ya había alertado a la población del peligro antes de salir. — I had already alerted the population of the danger before leaving.
- Ellos alertaban a los vecinos del incendio cuando eran jóvenes. — They used to alert the neighbours about the fire when they were young.
Common mistakes
- Wrong: Yo alerta a la población del peligro. — Right: Yo alerto a la población del peligro. — The person matters: alerta is the él/ella/Ud. form, while the yo form is alerto. Using the third-person form with yo is one of the most common beginner errors.
- Wrong: Ayer yo alerto a los vecinos del incendio. — Right: Ayer yo alerté a los vecinos del incendio. — The present and the preterite are different tenses: alerto is happening now, while alerté is a finished action in the past. Use the preterite with ayer.
- Wrong: Treating alertar and avisar as identical in every context. — Right: Alertar means to alert, while avisar means to warn or notify. — They overlap, but each has uses the other does not: alertar fits sentences such as Alerto a la población del peligro, while avisar belongs in a different sentence. Check the meaning you want before choosing.
- Wrong: Yo soy alertado a los vecinos del incendio. — Right: Yo he alertado a los vecinos del incendio. — Spanish perfect tenses use haber, not ser: he alertado, has alertado, ha alertado. Ser plus the participle makes a passive, not a perfect tense.
- Wrong: De niño, yo alerté a la policía del robo todos los días. — Right: De niño, yo alertaba a la policía del robo todos los días. — For a repeated habit in the past, use the imperfect (alertaba), not the preterite. The preterite (alerté) is for one finished action.
Quiz: test yourself
Ten questions on alertar. Choose the right form, then check the answer key below.
Complete the sentence: Yo ___ a la población del peligro. (present tense) A. alerto B. alertas C. alerta D. alertamos
Complete the sentence: Ayer, él ___ a los vecinos del incendio. (preterite) A. alerté B. alertaste C. alertaron D. alertó
Complete the sentence: Antes, nosotros ___ a la policía del robo. (imperfect) A. alertabas B. alertaban C. alertábamos D. alertaba
Complete the sentence: Mañana, tú ___ sobre la tormenta que viene. (future) A. alertaremos B. alertarás C. alertaré D. alertará
Complete the sentence: Yo ___ a la población del peligro si pudiera. (conditional) A. alertaría B. alertarías C. alertarían D. alerto
Complete the sentence: Espero que él ___ a los vecinos del incendio. (present subjunctive) A. alertes B. alertemos C. alerto D. alerte
Complete the sentence: Si yo ___ a la policía del robo, todo cambiaría. (imperfect subjunctive, -ra form) A. alertáramos B. alerto C. alertara D. alertaras
Complete the sentence: Nosotros ___ sobre la tormenta que viene. (present perfect) A. han alertado B. hemos alertado C. he alertado D. has alertado
Complete the command: ¡___ a la población del peligro! (affirmative imperative, tú) A. alerta B. alerte C. alertemos D. alertad
Which is the gerund of alertar, used with estar for the progressive? A. alertado B. alerto C. alerté D. alertando
Answer key
- alerto — The first-person present of alertar is alerto. The other options are the tú, él/ella and nosotros forms.
- alertó — The third-person preterite of alertar is alertó, the form for a single finished action in the past.
- alertábamos — The nosotros imperfect of alertar is alertábamos, used here for a repeated past habit.
- alertarás — The second-person future of alertar is alertarás.
- alertaría — The first-person conditional of alertar is alertaría, the form for what would happen.
- alerte — After espero que, the subjunctive is required: the third-person present subjunctive of alertar is alerte.
- alertara — The first-person imperfect subjunctive (-ra) of alertar is alertara.
- hemos alertado — The nosotros present perfect of alertar is hemos alertado: hemos + alertado.
- alerta — The affirmative tú imperative of alertar is alerta.
- alertando — The gerund of alertar is alertando: estoy alertando. The participle alertado is used with haber instead.
Frequently asked questions
What does alertar mean in English?
Alertar means to alert. It is used in everyday situations such as Alerto a la población del peligro. The exact English wording depends on the context, but the core meaning stays the same across the tenses.
Is alertar regular or irregular?
Alertar is a fully regular -ar verb, so every tense follows the standard endings for its class. Once you know the regular pattern, you can produce every form on this page, including alerto in the present and alerté in the preterite.
What is the difference between alertar and avisar?
Alertar means to alert, while avisar means to warn or notify. They are easy to confuse because they appear in similar situations, but they are not interchangeable: use alertar when you mean to alert, as in Alerto a la población del peligro, and use avisar for to warn or notify. When in doubt, check the object of the sentence — it usually shows which verb fits.
How do I say “I alert” in the past?
It depends on the kind of past. For one finished action, use the preterite: yo alerté a los vecinos del incendio. For a repeated habit or background in the past, use the imperfect: yo alertaba a la policía del robo. For something that has just happened, use the present perfect: yo he alertado a los vecinos del incendio.
How do I practise alertar?
Start with the present tense table, then drill the preterite and the imperfect, since those two past tenses cause the most mistakes. Try the alertar examples and quiz page for more sentences, and use the Spanish Verb Quiz to test the forms under pressure.
Related links
- Alertar in the present tense — the full present-tense table for alertar.
- Alertar examples and quiz — more example sentences and practice for alertar.
- Spanish verbs — the Spanish hub, with every verb and tense guide.
- Alegar conjugation — another -ar verb to compare with alertar.
- Alojar conjugation — another -ar verb to compare with alertar.
- Alarmar conjugation — another -ar verb to compare with alertar.
- Spanish Verb Conjugator — conjugate any Spanish verb in every tense.
- Spanish Verb Quiz — test yourself on real conjugated forms.