Deber means 'must' or 'to have to', and it is the verb you reach for to talk about obligation and what people should do. It is a regular -er verb, which makes it refreshingly predictable, but it has a couple of meanings worth keeping straight. Followed directly by an infinitive it expresses duty (debo estudiar, I must study). With de added (deber de), it expresses probability instead (debe de estar en casa, he must be at home). It also means 'to owe': te debo diez euros. For exams, the conditional debería ('should') is the real prize, because it is the natural way to give advice, and it instantly raises the sophistication of your Spanish.
Quick facts
Deber (to owe / should) is a regular -er verb.
Real sentences across different tenses — the kind of thing you'd actually say or write.
Deber + infinitive expresses duty: debo terminar mis deberes (I must finish my homework).
The conditional debería means 'should': deberías descansar (you should rest).
Deber de + infinitive expresses a guess: debe de ser tarde (it must be late).
Deber can mean to owe money: ¿cuánto te debo? (how much do I owe you?).
Fixed expressions worth knowing — they come up in listening, reading and writing tasks.
Idiomatic expressions
Deber + infinitive = obligation (debo estudiar = I must study), but deber DE + infinitive = probability (debe de estar en casa = he must be at home). Many learners drop the de and lose the meaning. Deberías… (you should) is the conditional and is perfect for giving advice in the exam.
deber is a regular -er verb — it follows the standard -er pattern in every tense. That makes it a good one to drill: if you know deber, you know the template for all regular -er verbs.
Type conjugations from memory and get instant feedback. That's how you actually build the automatic recall the exam needs — not from reading tables.
Practice deber now →Three questions, no account needed. Type the form, then press Enter or tap Check.
yo: debo, tú: debes, él: debe, nosotros: debemos, vosotros: debéis, ellos: deben
The past participle is debido (he debido) and the gerund is debiendo (estoy debiendo).
Verbs that are easy to confuse with deber or that behave like it.
Deber is on the AQA, Edexcel and Eduqas GCSE Spanish vocabulary lists. Compare the exam boards.
Written by Daniel Holmes for GCSE & A-Level Spanish students.