Deber Conjugation: All Spanish Tenses

Deber (must, ought to; to owe) is a very common verb and it is completely regular: it follows the -er verb pattern in every tense, so it serves as a model for that conjugation. It is also a modal verb: deber + infinitive expresses obligation or duty (debo estudiar - I must study), while deber de + infinitive expresses supposition or probability (deben de ser las cinco - it must be about five).

Indicative Tenses of Deber

Deber in the Present (Presente)

Current obligations and debts: Debo terminar este trabajo hoy (I must finish this work today).

Present tense rules →

Deber in the Preterite (Pretérito indefinido)

An obligation or debt at a specific past moment: Debí avisarte antes (I should have warned you earlier).

Preterite rules →

Deber in the Present Perfect (Pretérito perfecto)

A recent obligation connected to the present: He debido pedir ayuda varias veces (I have had to ask for help several times).

Present perfect rules →

Deber in the Imperfect (Pretérito imperfecto)

Habitual or ongoing obligations in the past: De joven debía trabajar los fines de semana (As a young man I had to work weekends).

Imperfect rules →

Deber in the Past Perfect (Pluscuamperfecto)

An obligation before another past action: Cuando llegué, ya había debido decidir (When I arrived, I had already had to decide).

Past perfect rules →

Deber in the Future (Futuro simple)

Future obligations: Mañana deberé presentar el informe (Tomorrow I will have to submit the report).

Future tense rules →

Deber in the Future Perfect (Futuro perfecto)

An obligation that will be fulfilled in the future: Para junio ya habré debido pagar todo (By June I will have had to pay everything).

Future perfect rules →

Deber in the Conditional (Condicional simple)

Advice and softened obligations: Deberías descansar más (You should rest more).

Conditional rules →

Deber in the Conditional Perfect (Condicional compuesto)

Unfulfilled obligations in the past: Habría debido llamarte, lo siento (I should have called you, I'm sorry).

Conditional perfect rules →

Subjunctive Tenses of Deber

Present Subjunctive of Deber (Presente de subjuntivo)

Wishes, doubts and emotions about an obligation: Espero que debas menos dinero pronto (I hope you owe less money soon).

Present subjunctive rules →

Present Perfect Subjunctive of Deber (Pretérito perfecto de subjuntivo)

Evaluating a recent past obligation: No creo que hayas debido tanto (I don't think you have owed that much).

Perfect subjunctive rules →

Imperfect Subjunctive of Deber (Pretérito imperfecto de subjuntivo)

Hypothetical conditions: Si debieras algo, te lo diría (If you owed anything, I would tell you).

Imperfect subjunctive rules →

Past Perfect Subjunctive of Deber (Pluscuamperfecto de subjuntivo)

Unreal hypotheses about the past: Si hubieras debido decidir, ¿qué harías? (If you had had to decide, what would you do?)

Past perfect subjunctive rules →

Imperative of Deber

The imperative of deber is rarely used in practice: to give orders or advice, Spanish prefers the conditional (deberías) or tener que. Still, these are its forms.

Affirmative Commands of Deber (Imperativo afirmativo)

Direct orders: Debe respeto a tus mayores (Show respect to your elders).

Affirmative commands rules →

Negative Commands of Deber (Imperativo negativo)

Prohibitions: No debas dinero a nadie (Don't owe money to anyone).

Negative commands rules →

Expressions with Deber

• Deber + infinitive - obligation or duty (debo estudiar para el examen - I must study for the exam)
• Deber de + infinitive - supposition or probability (deben de ser las cinco - it must be about five)
• Cumplir con su deber - to do one's duty
• Deber dinero - to owe money to someone