Devoir in French: Must, Have To, and Owe

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concept: fr-a1-devoir lang: fr ui: en title: Devoir in French: Must, Have To, and Owe description: >- Learn the present tense of French devoir for obligations, necessity, likely conclusions, and debts, with examples and common mistakes. generation: article: version: native-ui-reference-v3.1 model: openai-codex/gpt-5.6-sol at: 2026-07-11T08:46:11Z reviews: spell-check: status: clean at: 2026-07-11T08:46:11Z score: 0 score-english: null score-coverage: null criteria: v7 language-mixing: status: clean at: 2026-07-11T00:00:00Z criteria: v2

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In Brief

Use a conjugated form of devoir + an infinitive (the basic form of a verb) to say that someone must or has to do something: Je dois partir means “I must leave” or “I have to leave.” The present-tense forms are dois, dois, doit, devons, devez, doivent. Without another verb, devoir can also mean to owe: Je te dois dix euros.

Overview

Devoir is one of the most useful irregular verbs in French. At A1 level, its main job is to express an obligation or something that is necessary: Nous devons travailler (“We must work”). It often corresponds to both English must and have to. French does not normally make the same sharp grammatical distinction between those two English expressions; context and tone tell you how strong or personal the obligation is.

The verb is irregular, which means its forms do not follow the ordinary pattern of regular -er verbs. However, the sentence pattern is simple: conjugate devoir for the person who has the obligation, then put the required action in the infinitive. In Tu dois appeler, dois agrees with tu, while appeler stays unchanged.

The same verb also has two other important meanings. It can express a debt—money, an object, or something less tangible that one person owes another. It can also express a likely conclusion: Elle doit être chez elle can mean “She must be at home.” The obligation pattern is the beginner priority; the probability meaning and some finer distinctions are covered later.

How It Works

Present-tense forms

Subject	Form of devoir	English guide
je	dois	I must / have to
tu	dois	you must / have to (informal singular)
il / elle / on	doit	he / she / one must; we have to with on
nous	devons	we must / have to
vous	devez	you must / have to (plural or formal)
ils / elles	doivent	they must / have to

Notice the three stems: doi- in the singular, dev- with nous and vous, and doiv- with ils/elles. The final letters are not a reliable guide to pronunciation. Je dois, tu dois, and il doit have the same ending sound; in ils doivent, the written -ent is silent, but the v is pronounced.

Obligation: devoir + infinitive

The basic structure is:

subject + conjugated devoir + infinitive

• Je dois travailler. — I have to work.
• Vous devez attendre. — You must wait.
• Elles doivent prendre le train. — They have to take the train.

Only devoir is conjugated. The infinitive remains in its dictionary form:

• Nous devons partir, not nous devons partons.
• Tu dois faire, not tu dois fais.

Unlike English have to, French devoir is followed directly by the infinitive. Do not insert à or de: say Je dois étudier, not je dois à étudier.

French subject pronouns reflect both number and social relationship. Use tu dois for one person you address informally, vous devez for several people, and usually vous devez for one person addressed formally. In everyday speech, on doit very often means “we have to,” alongside the more formal or deliberate nous devons.

Questions

All common French question patterns work with devoir:

• Tu dois partir ? — Do you have to leave? (informal speech, rising intonation)
• Est-ce que tu dois partir ? — Do you have to leave? (neutral)
• Dois-tu partir ? — Must you leave? (formal or careful style)

With a question word, place it according to the question pattern you choose:

• Quand est-ce que nous devons partir ? — When do we have to leave?
• Pourquoi devez-vous attendre ? — Why must you wait?

In inversion, a hyphen joins the verb and subject pronoun: dois-tu, doit-il, devons-nous.

Negation

Put ne ... pas around the conjugated form of devoir:

• Je ne dois pas oublier. — I must not forget / I am not supposed to forget.
• Nous ne devons pas entrer. — We must not enter.

In ordinary conversation, speakers often omit ne: Je dois pas oublier. Learn and use the full form in careful writing.

There is an important English contrast here. Je ne dois pas partir normally means “I must not leave” or “I am not supposed to leave,” not “I do not have to leave.” To express lack of necessity, French often uses ne pas avoir besoin de:

• Je n’ai pas besoin de partir. — I do not have to leave.
• Vous n’avez pas besoin de réserver. — You do not need to book.

Context can sometimes make a negated devoir sound like lack of necessity, especially in casual French, but the avoir besoin de construction avoids ambiguity.

Owing money, things, or thanks

When devoir means “to owe,” it does not need a following infinitive. What is owed is the direct object (the thing directly affected by the verb), and the person it is owed to is introduced by à or represented by an indirect-object pronoun (a short word such as me, te, or lui meaning “to me,” “to you,” or “to him/her”).

• Je dois vingt euros à Léa. — I owe Léa twenty euros.
• Je lui dois vingt euros. — I owe him/her twenty euros.
• Tu me dois un café. — You owe me a coffee.
• Nous vous devons des excuses. — We owe you an apology.

In Je te dois combien ?, te means “to you,” while combien asks for the amount owed. In standard written French, put a space before the question mark: Combien ?

Examples in Context

French	English	Note
Je dois étudier ce soir.	I have to study tonight.	Everyday necessity
Tu dois faire tes devoirs.	You have to do your homework.	Devoirs as a plural noun means homework
Elle doit prendre ses médicaments.	She must take her medication.	Necessary action
On doit acheter du pain.	We have to buy some bread.	Conversational on for “we”
Nous devons partir avant huit heures.	We must leave before eight.	First-person plural
Vous devez montrer votre passeport.	You must show your passport.	Rule or official requirement
Ils doivent finir le projet demain.	They have to finish the project tomorrow.	Third-person plural
Est-ce que je dois réserver ?	Do I have to book?	Asking whether something is necessary
Quand devons-nous payer ?	When must we pay?	Inversion in a careful question
Tu ne dois pas toucher à ça.	You must not touch that.	Prohibition or strong warning
Vous n’avez pas besoin de venir lundi.	You do not have to come on Monday.	Lack of necessity, not prohibition
Je te dois combien ?	How much do I owe you?	Asking about a debt
Marc me doit cinquante euros.	Marc owes me fifty euros.	me identifies the person owed
Nous vous devons une explication.	We owe you an explanation.	A nonfinancial debt
Il doit être au bureau.	He must be at the office.	A likely conclusion, not an obligation

Common Mistakes

Conjugating both verbs

• Wrong: Nous devons partons maintenant.
• Right: Nous devons partir maintenant.
• Why: Conjugate devoir only. The second verb remains an infinitive: partir.

Treating devoir like a regular -er verb

• Wrong: Ils devoient travailler.
• Right: Ils doivent travailler.
• Why: Devoir is irregular. Learn its three present stems: doi-, dev-, and doiv-.

Adding a preposition before the infinitive

• Wrong: Je dois à appeler ma mère.
• Right: Je dois appeler ma mère.
• Why: Devoir takes an infinitive directly. English “have to” does not mean that French needs à.

Using negated devoir for “do not have to”

• Misleading: Vous ne devez pas venir.
• Clear correction: Vous n’avez pas besoin de venir.
• Why: The first sentence is usually understood as “You must not come” or “You are not supposed to come.” Use ne pas avoir besoin de when an action is optional.

Confusing devoir the verb with les devoirs

• Wrong meaning: interpreting Je fais mes devoirs as “I do my obligations.”
• Right: Je fais mes devoirs means “I do my homework.”
• Why: Un devoir is a duty or assignment, and the plural les devoirs commonly means homework. It is a noun here, not a conjugated verb.

Forgetting who owes whom

• Wrong: Je dois lui dix euros.
• Right: Je lui dois dix euros.
• Why: An unstressed object pronoun normally comes before the conjugated verb: je lui dois. With a named person, use à: Je dois dix euros à Paul.

Usage Notes

“Must” and “have to” do not map one-to-one

English often uses must for an obligation presented by the speaker and have to for an outside requirement, although real usage is more flexible. French commonly uses devoir for both:

• Je dois appeler mon frère. — I must / have to call my brother.
• Les visiteurs doivent porter un badge. — Visitors must / have to wear a badge.

If the precise source of the obligation matters, add context: Le règlement dit que... (“The rules say that...”), Mon médecin m’a dit de... (“My doctor told me to...”), or Il faut... (“It is necessary to...”).

Devoir versus il faut

Both can express necessity, but they organize the sentence differently. Devoir names the person responsible as its subject:

• Nous devons partir. — We must leave.

Il faut is impersonal: its grammatical il does not refer to a person or thing. It presents the action as generally necessary:

• Il faut partir. — It is necessary to leave / We need to leave.

At beginner level, use devoir when you want to say clearly who must act. You will often hear il faut for advice, rules, and general needs.

Strength depends on context and tone

Devoir can sound like a strict rule, practical necessity, advice, or self-reminder:

• Vous devez attacher votre ceinture. — a rule
• Je dois acheter du lait. — a practical need or reminder
• Tu dois voir ce film ! — an enthusiastic recommendation: “You have to see this film!”

The verb itself does not assign one fixed level of force. Situation, intonation, and added words do that work.

Beyond the Basics / Advanced Use

You do not need to master these uses at A1, but they explain many sentences you will meet later.

A likely conclusion

Devoir + infinitive can express probability rather than obligation. The speaker draws a strong conclusion from available information:

• Il doit être fatigué après ce voyage. — He must be tired after that journey.
• Elles doivent déjà connaître la réponse. — They must already know the answer.

Ask whether the subject is being required to act. If no one can meaningfully require the state, probability is likely. Il doit être malade normally means “He must be ill,” not that he has an obligation to be ill.

Softer advice with the conditional

The conditional mood (a verb form often used for hypothetical ideas or polite suggestions) makes devoir less direct:

• Tu devrais te reposer. — You should rest.
• Vous devriez vérifier l’adresse. — You should check the address.

Compare Tu dois partir (“You must/have to leave”) with Tu devrais partir (“You should leave”). The conditional forms belong to a later stage of study, but this contrast is extremely common.

Obligation in other time frames

French changes the tense of devoir to place the necessity in the past or future:

• J’ai dû annuler le rendez-vous. — I had to cancel the appointment.
• Nous devrons attendre. — We will have to wait.

Dû is the past participle (the verb form used with an auxiliary such as avoir to build a compound past tense). Its circumflex distinguishes it in writing from du, the contraction of de + le. Past-tense devoir can carry nuances that depend heavily on tense and context, so study those forms with the relevant past-tense lesson rather than simply replacing every English “must have” word for word.

A debt can be figurative

Owing is not limited to money:

• Je lui dois la vie. — I owe him/her my life.
• Nous devons cette réussite à toute l’équipe. — We owe this success to the whole team.
• Je vous dois des excuses. — I owe you an apology.

The last expression is useful in formal situations. In everyday conversation, Je suis désolé(e) may be more direct, but Je vous dois des excuses emphasizes that an apology is deserved.

Practice Tips

1. Build the six forms from one action. Choose an infinitive such as partir and say je dois partir, tu dois partir, il doit partir, nous devons partir, vous devez partir, ils doivent partir. Repeat with three everyday actions so the changing form of devoir stands out.
2. Practice the three-way meaning contrast. Sort sentences into obligation (Je dois travailler), conclusion (Il doit dormir), and debt (Je te dois dix euros). Look at what follows devoir and at the wider context rather than translating the verb in isolation.
3. Pair prohibition with optionality. Learn two complete models together: Tu ne dois pas entrer (“You must not enter”) and Tu n’as pas besoin d’entrer (“You do not have to enter”). This prevents one of the most consequential English-to-French mistakes.

Related Concepts

• Prerequisite: Regular -ER Verbs — provides the basic ideas of subjects, infinitives, and present-tense conjugation before you learn this irregular verb.