Using the Spanish Verb ‘Deber’

Common verb often used to express obligation

se venden diarios
¿Qué diario debo comprar? (Which newspaper should I buy?).

Juanedc.com / Creative Commons.

The Spanish verb deber is quite common and can be used to express obligation or that something that is likely. 

Key Takeaways: Using the Spanish Verb 'Deber'

  • The everyday verb deber is most often used to express that someone has a debt or is obligated to do something.
  • The phrase deber de can be used to indicate that something is highly probable.
  • In the preterite, deber is used to indicate that something should have been done.

Expressing Obligation

When used in this way, deber is frequently similar in meaning to the English "must," "should," or "ought":

  • Debes estudiar tus lecciones. (You ought to study your lessons.)
  • ¿Qué carro debo comprar? (Which car should I buy?)
  • Alguien deberá hablar de todo esto. (Someone will have to talk about all this.)
  • No debe dormirse después de comer. (He shouldn't go to sleep after eating.)

The tone of deber to express obligation can be softened by using the conditional form instead of the present tense, although the difference isn't always translatable. When telling someone what he or she should be doing, using the conditional can come across as more polite:

  • No deberías abrir un blog si vas a hablar de temas personales. (You shouldn't start a blog if you're going to talk about personal subjects.)
  • La Fuerza Aerea debería comprar mejores aviones de combate. (The Air Force should buy better combat planes.)
  • Hay 25 libros que deberíamos leer antes de cumplir los 30. (There are 25 books we should read before we reach our 30s.)

Expressing a Debt

When used with a noun direct object, deber can usually be translated as "owe."

  • No me debes nada. (You don't owe me anything.)
  • El gobierno le debe más de $3 millones a mi madre. (The government owes my mother more than $3 million.)
  • Siempre te voy a deber el haberme levantado cuando tan abajo estaba. (I am always going to owe you for having lifted me up when I was so low.)

Expressing Strong Probability

The phrase debes de is used to refer to a strong likelihood. In such cases, it is often the equivalent of the English "must" when "must" isn't used to express obligation:

  • No debiste de firmar nada. (You must not have signed anything.)
  • Debo de ser anormal. (I must be abnormal.)
  • Deben de estar en buena condición. (In all likelihood, they are in good condition.)

It is very common in some areas, especially in speech, to drop the de in sentences such as those above. However, out of context, doing so would make the sentences ambiguous. Thus while "​debías de verme" can mean only "you must have seen me," "debías verme" can mean either "you must have seen me" or "you ought to have seen me." In that case, you would need to know the context to understand what was meant.

On occasion, in some regions, you may hear deber de to express obligation. However, this usage is frowned upon by grammarians and should not be imitated if you are learning the language.

Using Deber in the Preterite

In the preterite tense, the rough equivalent of the simple past tense in English, deber can be used to indicate that something should have been done.

  • Son las palabras que no debiste decir. (They are the words you shouldn't have said.)
  • Pedro debió pedir disculpas a sus empleados tras la difusión del video. (Pedro should have asked for forgiveness from his employees after the video was broadcast.)
  • Debí ver que esto iba a ocurrir. (I should have seen that this was going to happen.)

Phrases Using Deber

These are among the common phrases using deber:

  • Deberse a (owing to, due to): El aumento de las enfermedades crónicas se debe a nuestro estilo de vida. (The increase in chronic illness is due to our lifestyle.)
  • Cumplir con su deber (to do or fulfill one's duty): Complí con mi deber de votar. (I fulfilled my duty to vote.)
  • No deberse a nadie (to be answerable to nobody): El presidente no se debe a nadie — salvo a todos los ciudadanos de todos y cada uno de los estados. (The president isn't answerable to anyone — except for all the citizens of each and every one of the states.)
  • Sentido del deber (sense of duty): No puedes decir que me falta el sentido del deber. (You can't say I lack a sense of duty.)