Deber Conjugation in Spanish
deber means “have to” in English, and it is one of the first verbs Spanish learners meet — it sits at number 15 in VerbFlow’s frequency list. You use it for obligation and duty, for giving advice, and for probability (deber de + infinitive). Because it comes up in everyday conversation so often, learning its forms properly pays off from the very first week. This page gives you the complete conjugation of deber — every tense, every person, the gerund and the past participle — with notes, examples, common mistakes and a quiz. Here is the verb in a natural sentence: “Yo debo estudiar más todos los días.” — “I have to study more every day.”
Quick facts
- Infinitive: deber
- English: to have to
- Verb type: Regular -er verb
- Irregular in: no tense — fully regular
- Gerund: debiendo
- Past participle: debido
- Auxiliary: haber (all perfect tenses are formed with haber + the past participle)
Full conjugation tables
Every form below comes from VerbFlow’s verified conjugation tables for deber. Learn the present tense first, then the preterite and the imperfect, and add the remaining tenses one at a time.
Present indicative
| Person | Form |
|---|---|
| yo | debo |
| tú | debes |
| él/ella/Ud. | debe |
| nosotros/as | debemos |
| vosotros/as | debéis |
| ellos/ellas/Uds. | deben |
Preterite
| Person | Form |
|---|---|
| yo | debí |
| tú | debiste |
| él/ella/Ud. | debió |
| nosotros/as | debimos |
| vosotros/as | debisteis |
| ellos/ellas/Uds. | debieron |
Imperfect
| Person | Form |
|---|---|
| yo | debía |
| tú | debías |
| él/ella/Ud. | debía |
| nosotros/as | debíamos |
| vosotros/as | debíais |
| ellos/ellas/Uds. | debían |
Future
| Person | Form |
|---|---|
| yo | deberé |
| tú | deberás |
| él/ella/Ud. | deberá |
| nosotros/as | deberemos |
| vosotros/as | deberéis |
| ellos/ellas/Uds. | deberán |
Conditional
| Person | Form |
|---|---|
| yo | debería |
| tú | deberías |
| él/ella/Ud. | debería |
| nosotros/as | deberíamos |
| vosotros/as | deberíais |
| ellos/ellas/Uds. | deberían |
Present perfect
| Person | Form |
|---|---|
| yo | he debido |
| tú | has debido |
| él/ella/Ud. | ha debido |
| nosotros/as | hemos debido |
| vosotros/as | habéis debido |
| ellos/ellas/Uds. | han debido |
Pluperfect (past perfect)
| Person | Form |
|---|---|
| yo | había debido |
| tú | habías debido |
| él/ella/Ud. | había debido |
| nosotros/as | habíamos debido |
| vosotros/as | habíais debido |
| ellos/ellas/Uds. | habían debido |
Future perfect
| Person | Form |
|---|---|
| yo | habré debido |
| tú | habrás debido |
| él/ella/Ud. | habrá debido |
| nosotros/as | habremos debido |
| vosotros/as | habréis debido |
| ellos/ellas/Uds. | habrán debido |
Conditional perfect
| Person | Form |
|---|---|
| yo | habría debido |
| tú | habrías debido |
| él/ella/Ud. | habría debido |
| nosotros/as | habríamos debido |
| vosotros/as | habríais debido |
| ellos/ellas/Uds. | habrían debido |
Present subjunctive
| Person | Form |
|---|---|
| yo | deba |
| tú | debas |
| él/ella/Ud. | deba |
| nosotros/as | debamos |
| vosotros/as | debáis |
| ellos/ellas/Uds. | deban |
Imperfect subjunctive (-ra)
| Person | Form |
|---|---|
| yo | debiera |
| tú | debieras |
| él/ella/Ud. | debiera |
| nosotros/as | debiéramos |
| vosotros/as | debierais |
| ellos/ellas/Uds. | debieran |
Imperative (affirmative)
| Person | Form |
|---|---|
| tú | debe |
| él/ella/Ud. | deba |
| nosotros/as | debamos |
| vosotros/as | debed |
| ellos/ellas/Uds. | deban |
Imperative (negative)
| Person | Form |
|---|---|
| tú | debas |
| él/ella/Ud. | deba |
| nosotros/as | debamos |
| vosotros/as | debáis |
| ellos/ellas/Uds. | deban |
Gerund and past participle
| Form | Spanish |
|---|---|
| Gerund | debiendo |
| Past participle | debido |
When to use each tense
Present indicative
The present indicative is used for habits, facts and things happening now. For example: “Yo debo estudiar más todos los días.” — “I have to study more every day.”
Preterite
The preterite is used for completed actions in the past. For example: “Tú debiste llegar a tiempo ayer.” — “You had to arrive on time yesterday.”
Imperfect
The imperfect is used for ongoing or habitual actions in the past, and background description. For example: “Él debía hacer la tarea antes.” — “He had to do the homework before.”
Future
The future is used for what will happen, predictions and probability. For example: “Yo deberé estudiar más mañana.” — “I will have to study more tomorrow.”
Conditional
The conditional is used for what would happen, polite requests and hypothetical situations. For example: “Tú deberías llegar a tiempo algún día.” — “You would have to arrive on time someday.”
Present perfect
The present perfect is used for recent past actions and life experience, formed with haber + the past participle. For example: “Él ha debido hacer la tarea esta semana.” — “He has had to do the homework this week.”
Pluperfect (past perfect)
The pluperfect (past perfect) is used for an action completed before another past action. For example: “Yo había debido estudiar más antes de la fiesta.” — “I had had to study more before the party.”
Future perfect
The future perfect is used for what will have happened by a point in the future. For example: “Tú habrás debido llegar a tiempo para mañana.” — “You will have had to arrive on time by tomorrow.”
Conditional perfect
The conditional perfect is used for what would have happened in a different past. For example: “Él habría debido hacer la tarea ayer.” — “He would have had to do the homework yesterday.”
Present subjunctive
The present subjunctive is used for wishes, doubts, emotions and opinions after que. For example: “Es importante que yo deba estudiar más.” — “It is important that i have to study more.”
Imperfect subjunctive (-ra)
The imperfect subjunctive (-ra) is used for the past subjunctive: wishes and hypotheticals about the past, and clauses after a past-tense trigger. For example: “Ojalá tú debieras llegar a tiempo.” — “I wish you had to arrive on time.”
Imperative (affirmative)
The imperative (affirmative) is used for direct commands and instructions. The imperative of deber gives a direct order; the negative forms use the present subjunctive pattern. For example: “¡Debe hacer la tarea!” — “You must do the homework!”
Imperative (negative)
The imperative (negative) is used for prohibitions and negative commands. The imperative of deber gives a direct order; the negative forms use the present subjunctive pattern. For example: “No debas estudiar más.” — “Do not have to study more.”
Example sentences
Ten natural sentences with deber, covering different tenses and persons. Say each one aloud, then cover the Spanish and try to produce it from the English.
- “Yo debo estudiar más todos los días.” — “I have to study more every day.”
- “Tú debiste llegar a tiempo ayer.” — “You had to arrive on time yesterday.”
- “Él debía hacer la tarea antes.” — “He had to do the homework before.”
- “Yo deberé llegar a tiempo mañana.” — “I will have to arrive on time tomorrow.”
- “Tú deberías estudiar más algún día.” — “You would have to study more someday.”
- “Él ha debido hacer la tarea esta semana.” — “He has had to do the homework this week.”
- “Yo había debido estudiar más antes de la fiesta.” — “I had had to study more before the party.”
- “Tú habrás debido llegar a tiempo para mañana.” — “You will have had to arrive on time by tomorrow.”
- “Es importante que él deba hacer la tarea.” — “It is important that he have to do the homework.”
- “¡Debe estudiar más!” — “You must study more!”
Common mistakes
1. Using the infinitive instead of a conjugated form
✗ Wrong: “Yo deber estudiar más.”
✓ Right: “Yo debo estudiar más.”
The infinitive deber never takes a subject. After yo you need the conjugated present form debo.
2. Confusing deber with tener
✗ Wrong: “Yo tengo estudiar más.”
✓ Right: “Yo debo estudiar más.”
Deber expresses duty; tener que also expresses obligation, and is more common in speech.
3. Using the wrong auxiliary in perfect tenses
✗ Wrong: “Yo soy debido estudiar más.”
✓ Right: “Yo he debido estudiar más.”
Spanish perfect tenses are always built with haber, never with ser. The correct form is he + the participle debido.
4. Dropping the written accent
✗ Wrong: “debi”
✓ Right: “debí”
The accent on debí is part of the spelling in the preterite. Without it the form looks like a different word, so always write the accent.
5. Using the indicative after a subjunctive trigger
✗ Wrong: “Ojalá tú debes estudiar más.”
✓ Right: “Ojalá tú debas estudiar más.”
After ojalá Spanish needs the subjunctive, so use debas here, not the indicative debes.
6. Using the preterite for a habitual past action
✗ Wrong: “Yo debí estudiar más antes.” (said of a repeated habit)
✓ Right: “Yo debía estudiar más antes.”
The preterite debí describes one finished action. For something you did regularly in the past, use the imperfect debía.
Quiz: test yourself
Ten questions on deber. Choose the right form, then check the answer key below.
What is the yo form of deber in the Present indicative?
- A) debes
- B) debe
- C) debemos
- D) debo
What is the él/ella/Ud. form of deber in the Preterite?
- A) debiste
- B) debimos
- C) debió
- D) debí
What is the nosotros/as form of deber in the Imperfect?
- A) debíais
- B) debíamos
- C) debía
- D) debías
What is the tú form of deber in the Future?
- A) deberás
- B) deberé
- C) deberá
- D) deberemos
What is the yo form of deber in the Conditional?
- A) deberías
- B) deberíamos
- C) deberíais
- D) debería
What is the él/ella/Ud. form of deber in the Present subjunctive?
- A) debamos
- B) debáis
- C) deba
- D) debas
What is the yo form of deber in the Imperfect subjunctive (-ra)?
- A) debierais
- B) debiera
- C) debieras
- D) debiéramos
What is the gerund of deber?
- A) debiendo
- B) pasando
- C) poniendo
- D) pareciendo
What is the past participle of deber?
- A) pasado
- B) puesto
- C) parecido
- D) debido
What does deber mean in English?
- A) to put
- B) to seem
- C) to have to
- D) to pass
Answer key
- D) debo — the yo form of deber in the present indicative is debo. The other options (debes, debe, debemos) are the same tense for different persons.
- C) debió — the él/ella/Ud. form of deber in the preterite is debió. The other options (debí, debiste, debimos) are the same tense for different persons.
- B) debíamos — the nosotros/as form of deber in the imperfect is debíamos. The other options (debía, debías, debía) are the same tense for different persons.
- A) deberás — the tú form of deber in the future is deberás. The other options (deberé, deberá, deberemos) are the same tense for different persons.
- D) debería — the yo form of deber in the conditional is debería. The other options (deberías, debería, deberíamos) are the same tense for different persons.
- C) deba — the él/ella/Ud. form of deber in the present subjunctive is deba. The other options (deba, debas, debamos) are the same tense for different persons.
- B) debiera — the yo form of deber in the imperfect subjunctive (-ra) is debiera. The other options (debieras, debiera, debiéramos) are the same tense for different persons.
- A) debiendo — the gerund of deber is debiendo; it is used with estar for the progressive. The other options are the gerunds of neighbouring verbs.
- D) debido — the past participle of deber is debido; perfect tenses use haber + debido. The other options are the participles of neighbouring verbs.
- C) to have to — deber means “to have to” in English. The other options are the meanings of neighbouring verbs.
Frequently asked questions
What does deber mean in English?
deber means “to have to”. You use it for obligation and duty, for giving advice, and for probability (deber de + infinitive). It is a core everyday verb, so its present-tense forms are worth learning first.
Is deber regular or irregular?
deber is regular -er verb, with no irregular tense — it follows the regular pattern throughout. The gerund is debiendo and the past participle is debido.
What are the gerund and past participle of deber?
The gerund is debiendo — use it with estar for actions in progress. The past participle is debido — use it with haber for the perfect tenses, as in he debido (I have had to).
What is the difference between deber and tener?
Deber expresses duty; tener que also expresses obligation, and is more common in speech. If you are unsure, check the full table for tener and compare the meanings in context.
How do I say “I have to” in Spanish?
Say “Yo debo estudiar más.” — “I have to study more every day.” The yo form of the present is debo, and it is the form you will use most often.
Related pages
- deber in the present tense — the full table and uses for this verb in its most practised tense.
- deber examples and quiz — more example sentences and practice questions for this verb.
- Spanish verbs — the full hub of Spanish conjugation pages.
- Pasar conjugation — another everyday Spanish verb.
- Poner conjugation — another everyday Spanish verb.
- Parecer conjugation — another everyday Spanish verb.
- Present tense guide — how the present tense works for regular verbs.
- Preterite tense guide — how the preterite works, and when to choose it over the imperfect.
- Verb Conjugator — practise deber with the interactive tool.
- Verb Quiz — practise deber with the interactive tool.