Have you ever wondered how to express moral obligations, strong recommendations, or things you “should” or “must” do in Spanish? While English uses modal verbs like “should,” “must,” or “ought to,” Spanish has a powerful and precise construction: Deber + Infinitive.
This essential construction expresses duty, moral obligation, or strong recommendations. Unlike “tener que” which focuses on external necessities, “deber” conveys a sense of moral responsibility or strong advice. In this complete guide, we’ll break down the formula, provide full conjugation charts across all tenses, and show you how to use this construction in authentic contexts.
What Does “Deber + Infinitive” Mean?
The phrase “Deber + [infinitive verb]” expresses moral obligation, duty, or strong recommendation. It’s equivalent to English “should,” “must,” or “ought to.”
The Core Formula:Subject + Conjugation of "Deber" + Infinitive Verb
- Debo estudiar más. (I should study more.)
- Debes ser honesto. (You must be honest.)
- Debemos ayudar a los demás. (We ought to help others.)
This construction carries a stronger moral weight than “tener que” and is used for giving advice, expressing duties, or stating what is right.
Complete Conjugation Patterns
Present Tense – Current Duties/Recommendations
| Pronoun | Conjugation | Example | English |
|---|---|---|---|
| Yo | debo | Debo estudiar más | I should study more |
| Tú | debes | Debes ser puntual | You should be punctual |
| Él/Ella/Ud. | debe | Debe decir la verdad | He/She should tell the truth |
| Nosotros | debemos | Debemos respetar a todos | We should respect everyone |
| Vosotros | debéis | Debéis practicar más | You all should practice more |
| Ellos/Uds. | deben | Deben ayudar | They should help |
Preterite Tense – Past Obligations (Specific)
| Pronoun | Conjugation | Example | English |
|---|---|---|---|
| Yo | debí | Debí estudiar ayer | I should have studied yesterday |
| Tú | debiste | Debiste llamarme | You should have called me |
| Él/Ella/Ud. | debió | Debió llegar temprano | He/She should have arrived early |
| Nosotros | debimos | Debimos ayudarles | We should have helped them |
| Vosotros | debisteis | Debisteis avisarnos | You all should have warned us |
| Ellos/Uds. | debieron | Debieron pagar | They should have paid |
Imperfect Tense – Past Duties/General Advice
| Pronoun | Conjugation | Example | English |
|---|---|---|---|
| Yo | debía | Debía estudiar cada día | I should study every day |
| Tú | debías | Debías ser más responsable | You should be more responsible |
| Él/Ella/Ud. | debía | Debía trabajar menos | He/She should work less |
| Nosotros | debíamos | Debíamos visitar a nuestros abuelos | We should visit our grandparents |
| Vosotros | debíais | Debíais practicar más | You all should practice more |
| Ellos/Uds. | debían | Debían ayudar en casa | They should help at home |
Future Tense – Future Duties
| Pronoun | Conjugation | Example | English |
|---|---|---|---|
| Yo | deberé | Deberé trabajar más | I will have to work more |
| Tú | deberás | Deberás estudiar medicina | You will have to study medicine |
| Él/Ella/Ud. | deberá | Deberá mudarse | He/She will have to move |
| Nosotros | deberemos | Deberemos ahorrar dinero | We will have to save money |
| Vosotros | deberéis | Deberéis ser más cuidadosos | You all will have to be more careful |
| Ellos/Uds. | deberán | Deberán cambiar | They will have to change |
Conditional Tense – Conditional Obligations/Advice
| Pronoun | Conjugation | Example | English |
|---|---|---|---|
| Yo | debería | Debería descansar más | I should rest more |
| Tú | deberías | Deberías llamar a tu madre | You should call your mother |
| Él/Ella/Ud. | debería | Debería ver a un médico | He/She should see a doctor |
| Nosotros | deberíamos | Deberíamos viajar más | We should travel more |
| Vosotros | deberíais | Deberíais practicar más | You all should practice more |
| Ellos/Uds. | deberían | Deberían ser más amables | They should be kinder |
Real-Life Examples by Tense:
Present Tense:
- Debo terminar mi tarea antes de salir. (I must finish my homework before going out.)
- Debes ser más paciente con los niños. (You should be more patient with children.)
- Los estudiantes deben respetar a sus profesores. (Students should respect their teachers.)
Past Tenses:
- Debí estudiar más para el examen. (I should have studied more for the exam.) – Preterite
- Debía visitar a mis abuelos cada semana. (I should visit my grandparents every week.) – Imperfect
- Debimos llegar más temprano ayer. (We should have arrived earlier yesterday.) – Preterite
Future & Conditional:
- Deberé trabajar más horas la próxima semana. (I will have to work more hours next week.)
- Deberías practicar español todos los días. (You should practice Spanish every day.)
- Deberíamos comer más saludable. (We should eat healthier.)
Common Mistakes to Avoid
- Confusing with “Deber de”: “Deber + infinitive” expresses obligation, while “deber de + infinitive” expresses probability or supposition.
- Debe estar en casa. (He must be at home. – obligation)
- Debe de estar en casa. (He must be at home. – probability)
- Using “deber” for mild suggestions: For mild suggestions, use “sería bueno que” or the subjunctive instead.
- Overusing preterite for regrets: While preterite can express regret, conditional is often more natural for “should have.”
Deber vs. Tener Que vs. Hay Que
Understanding the nuances between these obligation expressions is crucial:
- Deber: Expresses moral obligation, duty, or strong recommendation
- Debes decir la verdad. (You must tell the truth.)
- Tener que: Expresses external necessity or obligation
- Tengo que trabajar para ganar dinero. (I have to work to earn money.)
- Hay que: Expresses general, impersonal obligation
- Hay que respetar las leyes. (One must respect the laws.)
Test Your Knowledge
Ready for the quiz? Practice Deber Que with Real Examples
Master Other Essential Spanish Structures
“Deber” is just one of many key Spanish verb constructions. Deepen your knowledge with our other guides:
- Spanish Verb Conjugation Tool – Practice conjugating any verb, including “deber,” in all tenses.
- Tener Que + Infinitive – Master expressing external obligations and necessities.
- Acabar de + Infinitive – Learn to express recent past actions.
- Ir A + Infinitive – Master the simple future tense.
- Haber Que + Infinitive – Learn impersonal obligation expressions.
Conclusion:
Mastering “Deber + Infinitive” across all tenses is essential for expressing moral obligations, duties, and strong recommendations in Spanish. By understanding the nuances between different obligation expressions and practicing the conjugations of “deber” in present, past, future, and conditional forms, you’ll be able to give advice, express duties, and discuss moral responsibilities with precision. Incorporate this powerful construction into your Spanish practice to communicate with greater depth and authenticity!
