Mastering The French Verb Devoir

Mastering the French Verb Devoir: Understanding its Versatility Across Tenses

Mastering the French verb devoir is an essential step in gaining fluency. This verb, meaning “must” or “to have”, is incredibly versatile, but its meaning can shift dramatically depending on the tense in which it’s used. You can download a PDF of this lesson guide in my private French Grammar Library.

If you’ve ever had a little trouble with the French verb devoir and its many meanings, you’re not alone. This one verb is a powerhouse of expression, switching between obligation, probability, and intention depending on the tense and context.

In this lesson, you’ll discover how devoir pairs directly with an infinitive—no prepositions required—and learn how its meaning shifts across tenses like the present, passé composé, imperfect, and conditional.

By the end, you’ll not only know when and how to use devoir, but you’ll also gain confidence in applying it naturally in everyday conversations.

Mastering the Verb Devoir in French

Introduction to Devoir

Let’s explore how the meaning of devoir changes across different tenses: present, passé composé, imperfect, and present conditional.

Followed Directly by an Infinitive

When devoir is followed by an infinitive, it does not require a preposition.

Je dois travailler.

I must work.

This construction is used to express obligation, necessity, or sometimes probability, depending on the tense.

Meanings Across Tenses

Present Tense: Expressing Obligation or Necessity

In the present tense, devoir most often expresses an obligation or necessity, equivalent to “must” or “have to” in English.

Je dois partir maintenant.

I must leave now.

Nous devons étudier pour l’examen.

We have to study for the exam.

It can also suggest strong probability or a logical assumption:

Il doit être fatigué après ce long voyage.

He must be tired after this long trip.

Person	Conjugation	Example
Je	dois	Je dois partir maintenant. I must leave now.
Tu	dois	Tu dois finir ton travail. You must finish your work.
Il/Elle/On	doit	Elle doit être malade. She must be sick.
Nous	devons	Nous devons étudier pour l’examen. We have to study for the exam.
Vous	devez	Vous devez écouter le professeur. You must listen to the teacher.
Ils/Elles	doivent	Ils doivent rentrer tôt. They must come home early.

Passé Composé: Expressing a Completed Obligation or Supposition

In the passé composé, devoir indicates an action that had to be done and was completed or an assumption in the past.

J’ai dû faire mes devoirs hier soir.

I had to do my homework last night.

Elle a dû oublier le rendez-vous.

She must have forgotten the appointment.

Key Difference from the Imperfect

In the passé composé, devoir implies that the obligation or action was carried out or that the supposition has been resolved. It reflects a specific, completed moment in time.

Obligation fulfilled:

J’ai dû partir tôt.

I had to leave early—and I did leave early.

Supposition resolved:

Elle a dû oublier ses clés.

She must have forgotten her keys—and it’s clear this happened.

Person	Conjugation	Example
Je	ai dû	J’ai dû faire mes devoirs hier soir. I had to do my homework last night.
Tu	as dû	Tu as dû partir tôt. You had to leave early.
Il/Elle/On	a dû	Il a dû pleuvoir cette nuit. It must have rained last night.
Nous	avons dû	Nous avons dû attendre longtemps. We had to wait a long time.
Vous	avez dû	Vous avez dû voir ce film. You must have seen this movie.
Ils/Elles	ont dû	Elles ont dû prendre un taxi. They had to take a taxi.

Imperfect: Expressing an Unfulfilled Obligation or Possibility

In the imperfect, devoir often conveys an action that was supposed to happen but may not have been completed. It is less forceful than the present tense and can suggest intention or expectation.

Je devais faire la vaisselle, mais je ne l’ai pas faite.

I was supposed to do the dishes, but I didn’t.

Ils devaient venir à 18 heures, mais ils sont arrivés plus tard.

They were supposed to come at 6 PM, but they arrived later.

Key Difference from the Passé Composé

In the imparfait, devoir expresses an obligation, intention, or expectation that was not necessarily completed. It suggests an ongoing or habitual idea without confirming whether the action took place.

Obligation not fulfilled:

Je devais faire mes devoirs, mais je ne les ai pas faits.

I was supposed to do my homework, but I didn’t do it.

Ongoing intention or uncertainty:

Nous devions partir à 10 heures.

We were supposed to leave at 10 a.m.—but it’s unclear if we did.

Person	Conjugation	Example
Je	devais	Je devais faire la vaisselle. I was supposed to do the dishes.
Tu	devais	Tu devais m’appeler hier. You were supposed to call me yesterday.
Il/Elle/On	devait	Elle devait aller à Paris. She was supposed to go to Paris.
Nous	devions	Nous devions partir à midi. We were supposed to leave at noon.
Vous	deviez	Vous deviez venir chez moi. You were supposed to come to my house.
Ils/Elles	devaient	Ils devaient arriver tôt. They were supposed to arrive early.

Present Conditional: Expressing Hypothetical or Polite Obligation

In the conditional, devoir conveys a hypothetical obligation, advice, or polite suggestion. It is equivalent to “should” or “ought to” in English.

Tu devrais dormir plus tôt.

You should sleep earlier.

Nous devrions écouter les conseils du professeur.

We should listen to the teacher’s advice.

Person	Conjugation	Example
Je	devrais	Je devrais étudier plus souvent. I should study more often.
Tu	devrais	Tu devrais dormir plus tôt. You should sleep earlier.
Il/Elle/On	devrait	Il devrait pleuvoir demain. It should rain tomorrow.
Nous	devrions	Nous devrions écouter les conseils. We should listen to the advice.
Vous	devriez	Vous devriez parler au médecin. You should talk to the doctor.
Ils/Elles	devraient	Elles devraient faire attention. They should pay attention.