Introduction

contagiar means “to infect, to pass on”. It belongs to the group of Spanish verbs that express “to infect, to pass on”, and once you can conjugate it you can say a surprising amount with a single verb. This page is the complete reference for contagiar: every tense, every person, the gerund and the past participle, with notes on usage, real example sentences, common mistakes, a quiz and frequently asked questions. contagiar is a regular -ar verb. If it is irregular in a tense, the note under that table says so plainly, and the forms in the table are the correct ones — copy them, do not guess them from the infinitive. A first example to fix the verb in your mind: “Yo contagio la gripe todos los días.” — “I infect the flu.”

Quick facts
Infinitive contagiar
English to infect, to pass on
Verb type Regular -ar verb
Gerund contagiando
Past participle contagiado
Auxiliary verb haber

Full conjugation tables

Gerund: contagiando · Past participle: contagiado

Present Indicative

Person Form
yo contagio
tú contagias
él/ella/Ud. contagia
nosotros/as contagiamos
vosotros/as contagiáis
ellos/ellas/Uds. contagian

The present tense describes habits, facts and what is happening now. For contagiar, the yo form is contagio, as in “Yo contagio la gripe.” — “I infect the flu.”

Preterite

Person Form
yo contagié
tú contagiaste
él/ella/Ud. contagió
nosotros/as contagiamos
vosotros/as contagiasteis
ellos/ellas/Uds. contagiaron

The preterite describes completed actions in the past — things that started and finished. For contagiar, the yo form is contagié, as in “Yo contagié la gripe.” — “I infected the flu.”

Imperfect

Person Form
yo contagiaba
tú contagiabas
él/ella/Ud. contagiaba
nosotros/as contagiábamos
vosotros/as contagiabais
ellos/ellas/Uds. contagiaban

The imperfect describes the past as background: habits, descriptions and actions in progress. For contagiar, the yo form is contagiaba, as in “Yo contagiaba la gripe.” — “I used to infect the flu.”

Future

Person Form
yo contagiaré
tú contagiarás
él/ella/Ud. contagiará
nosotros/as contagiaremos
vosotros/as contagiaréis
ellos/ellas/Uds. contagiarán

The future tense states what will happen. It is also used for predictions and promises. For contagiar, the yo form is contagiaré, as in “Yo contagiaré la gripe.” — “I will infect the flu.”

Conditional

Person Form
yo contagiaría
tú contagiarías
él/ella/Ud. contagiaría
nosotros/as contagiaríamos
vosotros/as contagiaríais
ellos/ellas/Uds. contagiarían

The conditional expresses what would happen: wishes, polite requests and hypothetical results. For contagiar, the yo form is contagiaría, as in “Yo contagiaría la gripe.” — “I would infect the flu.”

Present Perfect

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

The present perfect connects the past with the present: something that has happened, often today or recently. For contagiar, the yo form is he contagiado, as in “Yo he contagiado la gripe.” — “I have infected the flu.”

Pluperfect

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

The pluperfect describes an event that happened before another past event. For contagiar, the yo form is había contagiado, as in “Yo había contagiado la gripe.” — “I had infected the flu.”

Future Perfect

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

The future perfect describes something that will already be finished by a future moment. For contagiar, the yo form is habré contagiado, as in “Yo habré contagiado la gripe.” — “I will have infected the flu.”

Conditional Perfect

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

The conditional perfect describes what would have happened under different conditions. For contagiar, the yo form is habría contagiado, as in “Yo habría contagiado la gripe.” — “I would have infected the flu.”

Present Subjunctive

Person Form
yo contagie
tú contagies
él/ella/Ud. contagie
nosotros/as contagiemos
vosotros/as contagiéis
ellos/ellas/Uds. contagien

The present subjunctive is used after expressions of wish, doubt, emotion and influence. For contagiar, the yo form is contagie, as in “Espero que yo contagie la gripe.” — “I hope that I infect the flu.”

Imperfect Subjunctive (-ra)

Person Form
yo contagiara
tú contagiaras
él/ella/Ud. contagiara
nosotros/as contagiáramos
vosotros/as contagiarais
ellos/ellas/Uds. contagiaran

The imperfect subjunctive is used in the past versions of subjunctive clauses, and after "si" in hypothetical sentences. For contagiar, the yo form is contagiara, as in “Si yo contagiara la gripe, ...” — “If I infected the flu, ...”

The -se variant of this tense follows the same pattern with -se instead of -ra: contagiara becomes contagiase, and the same change applies to every person. Both variants mean the same thing; -ra is more common in everyday speech.

Imperative (affirmative)

Person Form
tú contagia
Ud. contagie
nosotros/as contagiemos
vosotros/as contagiad
Uds. contagien

Imperative (negative)

Person Form
tú contagies
Ud. contagie
nosotros/as contagiemos
vosotros/as contagiéis
Uds. contagien

The imperative is for orders, requests and advice. The affirmative tú form is contagia, as in “¡Contagia la gripe” — “Infect the flu” For the negative imperative, Spanish uses the subjunctive forms: no contagies. Note that the affirmative and negative forms differ, so check the table above before you give an order with contagiar.

Example sentences

Here are ten sentences with contagiar, covering different tenses and persons. Read each one out loud, then read the translation, and notice how the verb form changes while the meaning stays the same.

  1. “Yo contagio la gripe cada día.” — “I infect the flu.”
  2. “Él contagia la gripe todos los días.” — “He infects the flu.”
  3. “Yo contagié la gripe ayer.” — “I infected the flu.”
  4. “Él contagió la gripe ayer.” — “He infected the flu.”
  5. “Yo contagiaba la gripe cuando era joven.” — “I used to infect the flu.”
  6. “Nosotros contagiaremos la gripe mañana.” — “We will infect the flu.”
  7. “Si pudiera, yo contagiaría la gripe.” — “If I could, i would infect the flu.”
  8. “Yo he contagiado la gripe hoy.” — “I have infected the flu.”
  9. “Espero que yo contagie la gripe.” — “I hope that I infect the flu.”
  10. “estoy contagiando la gripe ahora mismo.” — “I am infecting the flu.”

Common mistakes

Forgetting the accent in the preterite

The yo preterite form is contagié, with an accent on the stressed vowel. Writing it without the accent — contagie — is a spelling error, and in speech the stress lands in the wrong place. Preterite yo forms that end in a vowel carry that accent, so check it every time you write the preterite of contagiar.

Mixing up present and preterite nosotros

For contagiar, the nosotros form is the same in the present and the preterite: contagiamos. Only the context tells you which tense is meant, so pay attention to the time words around it — cada día points to the present, ayer points to the preterite. Do not invent a different form for one of the tenses.

Using ser instead of haber in perfect tenses

Spanish perfect tenses always use haber, never ser: yo he contagiado la gripe. English speakers sometimes reach for soy because English uses to be in some passives, but soy contagiado is not the present perfect of contagiar — it is a passive construction with a different meaning.

Confusing contagiar with conservar

contagiar and conservar look similar, and learners mix them up. They are different verbs with different meanings, so check which one the sentence needs before you conjugate. If you can substitute the English meaning of contagiar — infect — the sentence needs contagiar; if it needs the meaning of conservar, use that verb instead.

Using the indicative after "espero que"

After espero que (I hope that), Spanish needs the subjunctive: Espero que yo contagie la gripe. Using the indicative — Espero que yo contagio — is one of the most frequent learner errors with contagiar. Whenever the main clause expresses a wish, doubt or emotion, switch to the subjunctive.

Quiz

Test yourself on the forms above. Choose the best answer, then check the key below.

1. What is the yo form of contagiar in the present?

  • A. contagias
  • B. contagia
  • C. contagiamos
  • D. contagio

2. What is the tu form of contagiar in the preterite?

  • A. contagiamos
  • B. contagiaste
  • C. contagié
  • D. contagió

3. What is the el form of contagiar in the imperfect?

  • A. contagiabas
  • B. contagiábamos
  • C. contagiabais
  • D. contagiaba

4. What is the nosotros form of contagiar in the future?

  • A. contagiará
  • B. contagiaremos
  • C. contagiaré
  • D. contagiarás

5. What is the vosotros form of contagiar in the present perfect?

  • A. he contagiado
  • B. has contagiado
  • C. ha contagiado
  • D. habéis contagiado

6. What is the ellos form of contagiar in the present subjunctive?

  • A. contagie
  • B. contagien
  • C. contagie
  • D. contagies

7. What is the yo form of contagiar in the preterite?

  • A. contagiaste
  • B. contagió
  • C. contagiamos
  • D. contagié

8. What is the tu form of contagiar in the imperfect?

  • A. contagiábamos
  • B. contagiabas
  • C. contagiaba
  • D. contagiaba

9. What is the el form of contagiar in the future?

  • A. contagiaré
  • B. contagiarás
  • C. contagiaremos
  • D. contagiará

10. What is the nosotros form of contagiar in the conditional?

  • A. contagiaría
  • B. contagiaríamos
  • C. contagiaría
  • D. contagiarías

Answer key

  1. contagio — The present table gives yo = contagio.
  2. contagiaste — The preterite table gives tu = contagiaste.
  3. contagiaba — The imperfect table gives el = contagiaba.
  4. contagiaremos — The future table gives nosotros = contagiaremos.
  5. habéis contagiado — The present perfect table gives vosotros = habéis contagiado.
  6. contagien — The present subjunctive table gives ellos = contagien.
  7. contagié — The preterite table gives yo = contagié.
  8. contagiabas — The imperfect table gives tu = contagiabas.
  9. contagiará — The future table gives el = contagiará.
  10. contagiaríamos — The conditional table gives nosotros = contagiaríamos.

Frequently asked questions

Is contagiar regular or irregular?

contagiar is a regular -ar verb. It follows the regular patterns for its ending in every tense. The tables on this page show the correct form for every person, so use them rather than guessing.

What is the past participle of contagiar?

The past participle of contagiar is contagiado. You use it with haber in the perfect tenses — he contagiado, había contagiado, habré contagiado — and after estar in passive-style descriptions. It is the regular participle for its verb class. Learn it together with the gerund contagiando and you have the two non-finite forms covered.

What is the gerund of contagiar?

The gerund of contagiar is contagiando. You use it with estar to describe an action in progress, as in estoy contagiando, and after verbs such as seguir and ir. Keep it distinct from the past participle contagiado, which belongs with haber, not with estar.

What is the yo form of contagiar in the present?

The yo form is contagio — “Yo contagio la gripe.” means “I infect the flu.” That is the form you will use most often when you talk about yourself. For other persons, use the present table above: tú contagias, él contagia, nosotros contagiamos, ellos contagian.

What is the difference between contagiar and conservar?

contagiar means “to infect, to pass on”, while conservar means “to preserve, to keep”. They share letters and sometimes a root, but they are different verbs. If your sentence means “to infect, to pass on”, use contagiar; if it is about the meaning of conservar, use conservar instead. Checking the English meaning first prevents most mix-ups.

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