Everything you need to know about the irregular French verb devoir
Devoir is one of the most common French verbs. It is irregular in conjugation and has a number of different meanings related to concepts like obligation and probability.
1. Obligation and necessity
Dois-tu étudier ce soir ?
Do you have to study tonight?
Elles doivent manger
They must / need to eat.
2. Probability and supposition
Il doit rentrer avant le dîner
He should / will probably be back before dinner.
Nous devons gagner plus cette année
We should earn more this year.
Elle doit être à l'école
She must be at school.
3. Expectation and intention
Je devais aller avec eux
I was supposed to go with them.
Il devait le faire, mais il a oublié
He was supposed to do it, but he forgot.
4. Fatalism and inevitability
Il devait perdre un jour
He had to / was bound to lose one day.
Elle ne devait pas l'entendre avant lundi
She wasn't to hear it until Monday.
Translating devoir
Devoir can be translated by should, must, ought to, have to, supposed to...
- the distinction between necessity and probability is not always clear:
Je dois faire la lessive
I should/must/have to do the laundry.
Il doit arriver demain
He is supposed to / should / has to arrive tomorrow.
To specify "must" rather than "should," add a word like absolument or vraiment:
Je dois absolument partir
I really have to go.
Nous devons vraiment te parler
We must speak to you.
To specify "should" rather than "must," use the conditional:
Tu devrais partir
You should leave.
Ils devraient lui parler
They should talk to him.
To talk about something that should have happened, use the conditional perfect of devoir plus the infinitive:
Tu aurais dû manger
You should have eaten.
J'aurais dû étudier
I should have studied.
Devoir as a transitive verb
When used transitively (and thus not followed by a verb), devoir means "to owe":
Combien est-ce qu'il te doit ?
How much does he owe you?
Pierre me doit 10 francs
Pierre owes me 10 francs.
Conjugations
Present tense
je dois
tu dois
il doit
nous devons
vous devez
ils doivent
Using Devoir
Conjugations of devoir Devoir vs falloir Expressions of obligation
Devoir vs Falloir - Confusing French Pairs
Obligation and Necessity
The French verbs devoir and falloir are used to express obligation and necessity in different ways. Each verb has another meaning when followed by a noun.
Devoir
When followed by an infinitive, devoir expresses obligation, probability, or supposition. When followed by a noun it means to owe.
Je dois partir
I have to, I must, I'm supposed to leave
Je dois 5 dollars
I owe 5 dollars
Je devais
I had to, I was supposed to, I owed
Je devrai / Je devrais
I will have to / I would have to, I should
J'ai dû manger
I had to eat, I must have eaten
J'aurais dû manger (vs j'aurais mangé)
I should have eaten (vs I would have eaten)
The past participle of devoir is dû. When dû is modified to agree with a direct object, it loses the circonflex: dus, due, dues.
Falloir
Falloir is stronger and somewhat more formal than devoir; it expresses necessity. Falloir can be used with an infinitive or the subjunctive. It is an impersonal verb, so it does
not conjugate for different subjects. In order to specify a person, you can use the subjunctive or an indirect object pronoun with the infinitive.
Il faut travailler
It is necessary to work, One needs to work.
Il me faut travailler, Il faut que je travaille
I need to work.
Il ne faut pas manger
One must not eat.
Il fallait manger
We had to eat.
Il ne nous faut pas manger, Il ne faut pas que nous mangions
We don't need to eat, We mustn't eat
When followed by a noun, falloir means to need.
Il me faut un stylo.
I need a pen.
Quick summary
Devoir
Falloir
Type of verb*
Personal
Impersonal
Register*
Normal
Formal/Normal
Meaning when followed by...
infinitive
must, to have to
subjunctive
noun
to be necessary/need to
to be necessary/need to
to owe
to need