French grammar · Intermediate
Devoir, Pouvoir and Vouloir: The Three French Modal Verbs
Devoir, pouvoir and vouloir are the three French modal verbs, covering must, can and want. All three are followed directly by an infinitive with no preposition, all three share the same singular-plural stem split, and all three change meaning depending on which tense you put them in.
Je dois partir, mais je peux revenir demain si tu veux.
I have to go, but I can come back tomorrow if you like.
What it is
These three verbs do not describe actions, they describe your relationship to an action: whether you are obliged to do it, able to do it, or willing to do it. French treats them as ordinary verbs that happen to take an infinitive, which means they conjugate fully in every tense, unlike English must and can.
Tu dois partir, tu peux partir, tu veux partir — trois phrases très différentes. — You must leave, you can leave, you want to leave: three very different sentences.
How to spot it
All three are followed straight by an infinitive with nothing in between. If you see dois, peux or veux with a preposition after them, the sentence is doing something else.
- Je dois travailler ce soir. — I have to work tonight.
- Tu peux m'aider ? — Can you help me ?
- Elle veut apprendre le japonais. — She wants to learn Japanese.
- Nous devons cent euros à la banque. — We owe the bank a hundred euros.
Devoir followed by a noun instead of an infinitive means to owe. That is the one place these verbs behave like ordinary transitive verbs.
Devoir Pouvoir Vouloir Quick Reference
The three verbs at a glance
| Verb | Core meaning | Present je / nous |
|---|---|---|
| devoir | must, have to, be supposed to | je dois / nous devons |
| pouvoir | can, be able to, be allowed to | je peux / nous pouvons |
| vouloir | want, be willing to | je veux / nous voulons |
| devoir (conditional) | should, ought to | je devrais |
| pouvoir (conditional) | could, might | je pourrais |
| vouloir (conditional) | would like | je voudrais |
| past participles | dû, pu, voulu | j'ai dû, j'ai pu, j'ai voulu |
| future stems | devr-, pourr-, voudr- | je devrai, je pourrai, je voudrai |
Common Devoir Pouvoir Vouloir Examples in French
The three verbs in the situations where each one belongs:
Obligation with Devoir
- Je dois rendre ce dossier avant vendredi.
- I have to hand in this file before Friday.
- Vous devez présenter une pièce d'identité.
- You must show identification.
- On doit se lever tôt demain.
- We have to get up early tomorrow.
- Le train doit arriver à midi.
- The train is due to arrive at noon.
The last example shows devoir meaning expected rather than obliged, which is very common with timetables.
Ability and Permission with Pouvoir
- Je peux porter ça tout seul.
- I can carry that on my own.
- On peut fumer sur la terrasse ?
- Can we smoke on the terrace ?
- Elle ne peut pas venir ce soir.
- She can't come tonight.
- Ça peut arriver à tout le monde.
- That can happen to anyone.
Pouvoir covers physical ability, permission and possibility. Savoir is used instead for learned skills.
Wanting with Vouloir
- Je veux comprendre ce qui s'est passé.
- I want to understand what happened.
- Ils veulent que nous restions.
- They want us to stay.
- Tu veux bien m'attendre cinq minutes ?
- Would you mind waiting five minutes for me ?
- Je voudrais réserver pour deux personnes.
- I'd like to book for two people.
Vouloir is the only one of the three that can take que plus a subjunctive clause.
All Three in the Conditional
- Tu devrais te reposer un peu.
- You should rest a bit.
- Pourriez-vous répéter, s'il vous plaît ?
- Could you repeat that, please ?
- Je voudrais un renseignement.
- I'd like some information.
- On pourrait dîner ensemble un soir.
- We could have dinner together one evening.
The conditional turns obligation into advice, ability into a polite request, and wanting into a courtesy.
What the Three Verbs Have in Common
Learning them together is efficient because they share almost all of their behaviour.
They Take a Bare Infinitive
No preposition ever comes between a modal and the verb it governs. This is unlike most French verbs, which need à or de before an infinitive.
Je dois répondre avant ce soir.
I have to reply before this evening.
modal + infinitive, nothing between.
The Stem Splits Between Singular and Plural
All three change stem for nous and vous. Dois becomes devons, peux becomes pouvons, veux becomes voulons, and the stem reverts for ils: doivent, peuvent, veulent.
Je peux, nous pouvons, ils peuvent.
I can, we can, they can.
Singular and ils share a stem; nous and vous share another.
Object Pronouns Go in Front of the Modal
Because the modal is the conjugated verb, any pronoun belonging to the infinitive still moves ahead of it, and negation wraps the modal alone.
Je ne peux pas te le dire.
I can't tell you.
ne + pronouns + modal + pas + infinitive.
The Conditional Is the Polite Register
Pourriez-vous, voudriez-vous and tu devrais are the standard forms for requests and advice. Their present-tense equivalents sound blunt in the same situations.
Vous pourriez fermer la porte ?
Could you close the door ?
Politeness lives in the conditional.
Only Vouloir Can Take Que
Devoir and pouvoir always keep an infinitive. Vouloir can switch to que plus the subjunctive when the second verb has a different subject.
Je veux qu'il vienne, mais je ne peux pas l'obliger.
I want him to come, but I can't force him.
vouloir que + subjonctif.
Common Mistakes with Devoir Pouvoir Vouloir
Incorrect: Je dois de partir maintenant. — I have to leave now.
Correct: Je dois partir maintenant. — I have to leave now.
Modal verbs take a bare infinitive. The de belongs to expressions like avoir besoin de and essayer de, not to devoir, pouvoir or vouloir.
Incorrect: Je peux nager très bien depuis l'enfance. — I can swim very well.
Correct: Je sais nager très bien depuis l'enfance. — I can swim very well.
For a skill you learned, French uses savoir, not pouvoir. Je peux nager would mean the conditions allow it today, as in the pool is open.
Incorrect: Nous peuvons vous aider. — We can help you.
Correct: Nous pouvons vous aider. — We can help you.
The peu- stem belongs to the singular and to ils. Nous and vous revert to pouv-, in the same way as nous devons and nous voulons.
Incorrect: Tu dois te reposer un peu, tu as l'air fatigué. — You should rest a bit, you look tired.
Correct: Tu devrais te reposer un peu, tu as l'air fatigué. — You should rest a bit, you look tired.
The present tu dois is an order. Advice between equals goes into the conditional, which is how French separates should from must, since it has no separate word for either.
The Three Verbs Conjugated Side by Side
Reading across the rows shows how parallel these verbs are. Each has a two-stem present, a doubled or shortened future stem, and an irregular subjunctive.
Present Tense
The forms you will use most. Notice that all three singular forms end in -s, -s, -t and that ils takes a doubled consonant or a stem change.
| Pronoun | devoir | pouvoir | vouloir |
|---|---|---|---|
| je / j' | dois | peux | veux |
| tu | dois | peux | veux |
| il / elle / on | doit | peut | veut |
| nous | devons | pouvons | voulons |
| vous | devez | pouvez | voulez |
| ils / elles | doivent | peuvent | veulent |
Puis-je is an old inverted form of je peux that survives in formal questions: puis-je vous aider ?
Conditional
The stems are devr-, pourr- and voudr-, and the endings are the imparfait ones. These are the forms that make French requests polite.
| Pronoun | devoir (devr-) | pouvoir (pourr-) | vouloir (voudr-) |
|---|---|---|---|
| je / j' | devrais | pourrais | voudrais |
| tu | devrais | pourrais | voudrais |
| il / elle / on | devrait | pourrait | voudrait |
| nous | devrions | pourrions | voudrions |
| vous | devriez | pourriez | voudriez |
| ils / elles | devraient | pourraient | voudraient |
The future is the same stems with the avoir endings: je devrai, je pourrai, je voudrai.
Subjunctive
All three are irregular, and puisse in particular turns up constantly after negative and indefinite antecedents.
| Pronoun | devoir | pouvoir | vouloir |
|---|---|---|---|
| je / j' | doive | puisse | veuille |
| tu | doives | puisses | veuilles |
| il / elle / on | doive | puisse | veuille |
| nous | devions | puissions | voulions |
| vous | deviez | puissiez | vouliez |
| ils / elles | doivent | puissent | veuillent |
Pouvoir is the only one with a single subjunctive stem all the way down: puiss-.
How the Tense Changes the Meaning
These verbs describe states, so moving them between tenses shifts what they mean, not just when they mean it. This is where most of the difficulty with them lies.
Devoir across the tenses
Present is obligation, imparfait is a standing obligation or a plan, passé composé is either a completed obligation or a deduction, and the conditional is advice.
- Je dois y aller.
- I have to go.
- Je devais y aller, mais j'ai annulé.
- I was supposed to go, but I cancelled.
- Il a dû rater son train.
- He must have missed his train.
- Tu devrais lui écrire.
- You should write to him.
The deduction reading of j'ai dû is decided entirely by context: elle a dû partir can be she had to leave or she must have left.
Pouvoir across the tenses
The imparfait describes a standing ability; the passé composé describes a single successful attempt. Negated in the passé composé it means the attempt failed.
- Je pouvais courir dix kilomètres à l'époque.
- I could run ten kilometres back then.
- J'ai pu réserver les billets.
- I managed to book the tickets.
- Je n'ai pas pu la joindre.
- I couldn't reach her.
- Il aurait pu nous prévenir.
- He could have warned us.
J'ai pu almost always means I succeeded, which is stronger than the English I could.
Vouloir across the tenses
The imparfait gives the state of wanting, the passé composé gives the decision or the attempt, and the negative passé composé means refused.
- Je voulais te poser une question.
- I wanted to ask you a question.
- Elle a voulu ouvrir la fenêtre.
- She tried to open the window.
- Ils n'ont pas voulu payer.
- They refused to pay.
- J'aurais voulu être là.
- I would have liked to be there.
Je voulais te demander is the standard polite way to introduce a request, softer than je veux te demander.
Devoir Pouvoir Vouloir FAQs
- How do you conjugate pouvoir in the present tense?
- Je peux, tu peux, il peut, nous pouvons, vous pouvez, ils peuvent. The past participle is pu and the future and conditional stem is pourr-, giving je pourrai and je pourrais.
- What is the difference between devoir, pouvoir and vouloir?
- Devoir is obligation, pouvoir is ability or permission, and vouloir is desire. Tu dois partir means you have to go, tu peux partir means you may go, and tu veux partir means you want to go.
- How do you say should in French?
- With devoir in the conditional: tu devrais, vous devriez. French has no separate word for should, so the mood of devoir carries the difference between must and ought to.
- Why do these verbs change stem for nous and vous?
- Because the stress fell on different syllables in Latin, and the unstressed forms evolved differently. That is why peux and pouvons no longer look alike, and the same split appears in dois and devons, veux and voulons.
- What does j'ai dû mean?
- Either I had to or I must have, depending on context. J'ai dû partir tôt is I had to leave early, while il a dû oublier is he must have forgotten. Only the situation tells the two apart.