Reforzar Conjugation in Spanish

The Spanish verb reforzar means to reinforce, and it is a verb you will use again and again once you know it. Reforzar means to strengthen something that already exists: a wall, a team, an idea, a security system. It is used for both physical reinforcement and for arguments and ideas. Like every Spanish verb, reforzar 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 Yo refuerzo los cimientos de la casa — "I reinforce the foundations of the house". 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.

The stem vowel changes in the stressed forms of the present: refuerzo, refuerzas, refuerza and refuerzan — but nosotros and vosotros keep the plain stem: reforzamos, reforzáis. The z of the stem becomes c before e: the preterite yo form is reforcé and the present subjunctive yo form is refuerce.

Quick facts

  • Infinitive: reforzar
  • English: to reinforce
  • Verb type: stem-changing -ar verb (o → ue)
  • Ending: -ar
  • Gerund: reforzando
  • Past participle: reforzado
  • Auxiliary verb: haber (all perfect tenses are formed with haber + reforzado)

Pronunciation is not listed on this page: the verified tables do not include IPA for reforzar, so no pronunciation is given rather than an invented one.

Full conjugation tables

Every form below comes from the verified conjugation tables for reforzar. The imperfect subjunctive is shown in its -ra forms; the -se forms use the same stem.

Present indicative

| Person | Form | |---|---|---| | yo | refuerzo | | tú | refuerzas | | él/ella/Ud. | refuerza | | nosotros/as | reforzamos | | vosotros/as | reforzáis | | ellos/ellas/Uds. | refuerzan |

Preterite

| Person | Form | |---|---|---| | yo | reforcé | | tú | reforzaste | | él/ella/Ud. | reforzó | | nosotros/as | reforzamos | | vosotros/as | reforzasteis | | ellos/ellas/Uds. | reforzaron |

Imperfect

| Person | Form | |---|---|---| | yo | reforzaba | | tú | reforzabas | | él/ella/Ud. | reforzaba | | nosotros/as | reforzábamos | | vosotros/as | reforzabais | | ellos/ellas/Uds. | reforzaban |

Future

| Person | Form | |---|---|---| | yo | reforzaré | | tú | reforzarás | | él/ella/Ud. | reforzará | | nosotros/as | reforzaremos | | vosotros/as | reforzaréis | | ellos/ellas/Uds. | reforzarán |

Conditional

| Person | Form | |---|---|---| | yo | reforzaría | | tú | reforzarías | | él/ella/Ud. | reforzaría | | nosotros/as | reforzaríamos | | vosotros/as | reforzaríais | | ellos/ellas/Uds. | reforzarían |

Present perfect

| Person | Form | |---|---|---| | yo | he reforzado | | tú | has reforzado | | él/ella/Ud. | ha reforzado | | nosotros/as | hemos reforzado | | vosotros/as | habéis reforzado | | ellos/ellas/Uds. | han reforzado |

Pluperfect

| Person | Form | |---|---|---| | yo | había reforzado | | tú | habías reforzado | | él/ella/Ud. | había reforzado | | nosotros/as | habíamos reforzado | | vosotros/as | habíais reforzado | | ellos/ellas/Uds. | habían reforzado |

Future perfect

| Person | Form | |---|---|---| | yo | habré reforzado | | tú | habrás reforzado | | él/ella/Ud. | habrá reforzado | | nosotros/as | habremos reforzado | | vosotros/as | habréis reforzado | | ellos/ellas/Uds. | habrán reforzado |

Conditional perfect

| Person | Form | |---|---|---| | yo | habría reforzado | | tú | habrías reforzado | | él/ella/Ud. | habría reforzado | | nosotros/as | habríamos reforzado | | vosotros/as | habríais reforzado | | ellos/ellas/Uds. | habrían reforzado |

Present subjunctive

| Person | Form | |---|---|---| | yo | refuerce | | tú | refuerces | | él/ella/Ud. | refuerce | | nosotros/as | reforcemos | | vosotros/as | reforcéis | | ellos/ellas/Uds. | refuercen |

Imperfect subjunctive (-ra)

| Person | Form | |---|---|---| | yo | reforzara | | tú | reforzaras | | él/ella/Ud. | reforzara | | nosotros/as | reforzáramos | | vosotros/as | reforzarais | | ellos/ellas/Uds. | reforzaran |

Imperative (affirmative)

| Person | Form | |---|---|---| | tú | refuerza | | él/ella/Ud. | refuerce | | nosotros/as | reforcemos | | vosotros/as | reforzad | | ellos/ellas/Uds. | refuercen |

Imperative (negative)

| Person | Form | |---|---|---| | tú | refuerces | | él/ella/Ud. | refuerce | | nosotros/as | reforcemos | | vosotros/as | reforcéis | | ellos/ellas/Uds. | refuercen |

Gerund and past participle

Form Spanish Use
Gerund reforzando with estar for the progressive: está reforzando
Past participle reforzado with haber for the perfect tenses: he reforzado

How to use each tense

Present indicative

Use the present for routines, general facts and what is happening right now. The stem vowel changes in the stressed forms of the present: refuerzo, refuerzas, refuerza and refuerzan — but nosotros and vosotros keep the plain stem: reforzamos, reforzáis. For reforzar, the present indicative looks like this in a real sentence: Yo refuerzo los cimientos de la casa — "I reinforce the foundations of the house".

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. The z of the stem becomes c before e: the preterite yo form is reforcé and the present subjunctive yo form is refuerce. For reforzar, the preterite looks like this in a real sentence: Ayer, yo reforcé la seguridad del edificio — "Yesterday, I reinforced the building's security".

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 reforzar, the imperfect looks like this in a real sentence: De niño, yo reforzaba el equipo con dos jugadores — "As a child, I used to reinforce the team with two players".

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 reforzar, the future looks like this in a real sentence: Mañana, yo reforzaré la idea con ejemplos — "Tomorrow, I will reinforce the idea with examples".

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 reforzar, the conditional looks like this in a real sentence: Yo reforzaría los cimientos de la casa si pudiera — "I would reinforce the foundations of the house if I could".

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 reforzar, the present perfect looks like this in a real sentence: Hoy, yo he reforzado la seguridad del edificio — "Today, I have reinforced the building's security".

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 reforzar, the pluperfect looks like this in a real sentence: Yo ya había reforzado el equipo con dos jugadores antes de salir — "I already had reinforced the team with two players before leaving".

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 reforzar, the future perfect looks like this in a real sentence: Para mañana, yo habré reforzado la idea con ejemplos — "By tomorrow, I will have reinforced the idea with examples".

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 reforzar, the conditional perfect looks like this in a real sentence: Yo habría reforzado los cimientos de la casa con más tiempo — "I would have reinforced the foundations of the house with more time".

Present subjunctive

Use the present subjunctive after expressions of wish, doubt, emotion and hope, such as espero que or quiero que. The stem vowel changes in the stressed forms of the present: refuerzo, refuerzas, refuerza and refuerzan — but nosotros and vosotros keep the plain stem: reforzamos, reforzáis. For reforzar, the present subjunctive looks like this in a real sentence: Espero que él refuerce la seguridad del edificio — "I hope he reinforces the building's security".

Imperfect subjunctive (-ra)

Use the imperfect subjunctive after past wishes and in si clauses about the past. The -ra forms are 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 reforzar, the imperfect subjunctive (-ra) looks like this in a real sentence: Si yo reforzara el equipo con dos jugadores, todo cambiaría — "If I reinforced the team with two players, everything would change".

Imperative (affirmative)

Use the affirmative imperative for direct commands, instructions and invitations. The stem vowel changes in the stressed forms of the present: refuerzo, refuerzas, refuerza and refuerzan — but nosotros and vosotros keep the plain stem: reforzamos, reforzáis. For reforzar, the imperative (affirmative) looks like this in a real sentence: Refuerza la idea con ejemplos. — "Reinforce the idea with examples.".

Imperative (negative)

Use the negative imperative, always with no, to tell someone not to do something. The stem vowel changes in the stressed forms of the present: refuerzo, refuerzas, refuerza and refuerzan — but nosotros and vosotros keep the plain stem: reforzamos, reforzáis. For reforzar, the imperative (negative) looks like this in a real sentence: No refuerces los cimientos de la casa. — "Do not reinforce the foundations of the house.".

Example sentences

Ten natural sentences with reforzar, covering different tenses and persons. Each one uses a form from the tables above.

  1. Yo refuerzo los cimientos de la casa — "I reinforce the foundations of the house"
  2. Mi amigo refuerza la seguridad del edificio — "My friend reinforces the building's security"
  3. Ayer, yo reforcé el equipo con dos jugadores — "Yesterday, I reinforced the team with two players"
  4. Antes, nosotros reforzábamos la idea con ejemplos — "Before, we used to reinforce the idea with examples"
  5. Mañana, tú reforzarás el muro con hormigón — "Tomorrow, you will reinforce the wall with concrete"
  6. Yo reforzaría los cimientos de la casa si tuviera más tiempo — "I would reinforce the foundations of the house if I had more time"
  7. Él ha reforzado la seguridad del edificio — "He has reinforced the building's security"
  8. Espero que él refuerce el equipo con dos jugadores — "I hope he reinforces the team with two players"
  9. Yo ya había reforzado la idea con ejemplos antes de salir — "I already had reinforced the idea with examples before leaving"
  10. Ellos reforzaban el muro con hormigón cuando eran jóvenes — "They used to reinforce the wall with concrete when they were young"

Common mistakes

  1. Wrong: Yo reforzo la seguridad del edificio. — Right: Yo refuerzo la seguridad del edificio. — reforzar is a stem-changing verb (o → ue): the stem vowel changes in the stressed present forms, so the yo form is refuerzo, not reforzo.
  2. Wrong: Ayer, yo reforzé el equipo con dos jugadores. — Right: Ayer, yo reforcé el equipo con dos jugadores. — The z of reforzar becomes c before e, so the preterite yo form is reforcé, never reforzé.
  3. Wrong: Espero que él refuerza la seguridad del edificio — Right: Espero que él refuerce la seguridad del edificio — After espero que, Spanish requires the subjunctive: Espero que él refuerce la seguridad del edificio — not the indicative Espero que él refuerza la seguridad del edificio.
  4. Wrong: Ayer, yo refuerzo el equipo con dos jugadores — Right: Ayer, yo reforcé el equipo con dos jugadores — Ayer points to a finished action in the past, so it needs the preterite: Ayer, yo reforcé el equipo con dos jugadores.
  5. Wrong: De niño, yo reforcé la idea con ejemplos todos los días — Right: De niño, yo reforzaba la idea con ejemplos todos los días — For a repeated habit in the past, use the imperfect, not the preterite: De niño, yo reforzaba la idea con ejemplos todos los días.

Quiz: test yourself

Ten questions on reforzar. Choose the right form, then check the answer key below.

  1. Complete the sentence: Yo ______ los cimientos de la casa — "I reinforce the foundations of the house" (present) A. reforzamos B. refuerzo C. refuerzas D. refuerza

  2. Complete the sentence: Él ______ la seguridad del edificio — "He reinforced the building's security" (preterite) A. reforzaste B. reforzamos C. reforzó D. reforcé

  3. Complete the sentence: Nosotros ______ el equipo con dos jugadores — "We used to reinforce the team with two players" (imperfect) A. reforzabais B. reforzábamos C. reforzaba D. reforzabas

  4. Complete the sentence: Tú ______ la idea con ejemplos — "You will reinforce the idea with examples" (future) A. reforzaré B. reforzará C. reforzaremos D. reforzarás

  5. Complete the sentence: Yo ______ el muro con hormigón — "I would reinforce the wall with concrete" (conditional) A. reforzaría B. reforzarías C. reforzaríamos D. reforzaríais

  6. Complete the sentence: Espero que él ______ los cimientos de la casa — "I hope he reinforces the foundations of the house" (present subjunctive) A. reforcéis B. refuerce C. refuerces D. reforcemos

  7. Complete the sentence: Si yo ______ la seguridad del edificio, todo cambiaría — "If I reinforced the building's security, everything would change" (imperfect subjunctive) A. reforzáramos B. reforzarais C. reforzara D. reforzaras

  8. Complete the sentence: Nosotros ______ el equipo con dos jugadores — "We have reinforced the team with two players" (present perfect) A. has reforzado B. ha reforzado C. hemos reforzado D. he reforzado

  9. Complete the sentence: No ______ la idea con ejemplos. — "Do not reinforce the idea with examples." (negative imperative) A. refuerce B. reforcemos C. reforcéis D. refuerces

  10. Which is the gerund of reforzar, used with estar for the progressive? A. reforzado B. refuerzo C. reforcé D. reforzando

Answer key

  1. refuerzo — The present form for yo is refuerzo.
  2. reforzó — The preterite form for él/ella/Ud. is reforzó.
  3. reforzábamos — The imperfect form for nosotros/as is reforzábamos.
  4. reforzarás — The future form for tú is reforzarás.
  5. reforzaría — The conditional form for yo is reforzaría.
  6. refuerce — The present subjunctive form for él/ella/Ud. is refuerce.
  7. reforzara — The imperfect subjunctive form for yo is reforzara.
  8. hemos reforzado — The present perfect form for nosotros/as is hemos reforzado.
  9. refuerces — The negative imperative form is refuerces.
  10. reforzando — The gerund of reforzar is reforzando: estoy reforzando. The participle reforzado is used with haber instead.

Frequently asked questions

What does reforzar mean in English?

reforzar means to reinforce. It is used in everyday situations such as Yo refuerzo los cimientos de la casa — "I reinforce the foundations of the house". The exact English wording depends on the context, but the core meaning stays the same across the tenses.

Is reforzar regular?

No. reforzar is a stem-changing -ar verb (o → ue). The stem vowel changes in the stressed forms of the present: refuerzo, refuerzas, refuerza and refuerzan — but nosotros and vosotros keep the plain stem: reforzamos, reforzáis. The nosotros and vosotros forms keep the plain stem, which is the part learners most often get right by accident.

What is the gerund and the past participle of reforzar?

The gerund is reforzando and the past participle is reforzado. Use the gerund with estar for the progressive, and the participle with haber for the perfect tenses.

How do I say "I reinforce" in the past?

It depends on the kind of past. For one finished action, use the preterite: Ayer, yo reforcé la seguridad del edificio — "Yesterday, I reinforced the building's security". For a repeated habit or background in the past, use the imperfect: De niño, yo reforzaba el equipo con dos jugadores — "As a child, I used to reinforce the team with two players". For something that has just happened, use the present perfect: Hoy, yo he reforzado la seguridad del edificio — "Today, I have reinforced the building's security".

What is the difference between reforzar and fortalecer?

Fortalecer and reforzar overlap, but reforzar often means adding support to a specific weak point, while fortalecer is more general strengthening, including of the body or the will. Reforzar means to strengthen something that already exists: a wall, a team, an idea, a security system. It is used for both physical reinforcement and for arguments and ideas.

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