devoir (présent)

Irregular Verb Devoir (Must/to Have to)

Level 1

Devoir is a versatile irregular verb used to say what someone must do, what is likely happening, or what someone owes.

How It Works

The verb devoir is essential for daily communication. Here is how to use it effectively:

1. Conjugation Pattern
It follows a three-stem pattern in the present tense:

  • doi- for singular: je dois, tu dois, il/elle/on doit
  • dev- for nous/vous: nous devons, vous devez
  • doiv- for 3rd person plural: ils/elles doivent

Note: Unlike pouvoir or vouloir, the singular endings are -s, not -x.

2. Expressing Obligation or Prohibition
When followed by an infinitive, it means 'must' or 'have to'.
Je dois partir. (I must leave.)
In the negative, ne pas devoir means 'must not'.
Tu ne dois pas fumer ici. (You must not smoke here.)

3. Expressing Probability or Expectation
It can mean 'must be' (probability) or 'supposed to' (expectation/schedule).
Il doit être fatigué. (He must be tired.)
Le train doit arriver à midi. (The train is supposed to arrive at noon.)

4. Expressing Debt and the Noun Form
When followed by a noun, it means 'to owe'.
Je te dois cinq euros. (I owe you five euros.)
Note that the noun form les devoirs (literally 'the obligations') is the standard French word for homework.

5. Devoir vs. Falloir
While devoir is personal, il faut is impersonal and general. Use devoir when you want to emphasize that a specific subject has the obligation.

Examples (5)

  1. Tu dois finir tes devoirs avant de sortir.

    You must finish your homework before going out.

    Word by Word: You must to-finish your homeworks before of to-go-out.

    Here, 'dois' expresses a direct obligation for the subject 'tu'.

  2. Il est déjà huit heures, ils doivent être arrivés.

    It is already eight o'clock; they must have arrived.

    Word by Word: It is already eight hours, they must to-be arrived.

    In this context, 'doivent' expresses a logical probability rather than a duty.

  3. Nous vous devons une explication.

    We owe you an explanation.

    Word by Word: We to-you owe an explanation.

    When followed by a noun (une explication), 'devoir' means 'to owe'.

  4. Je dois aller à la banque ce matin.

    I have to go to the bank this morning.

    Word by Word: I must to-go to the bank this morning.

    Notice that there is no preposition between 'dois' and 'aller'.

  5. Vous devez manger pour rester en bonne santé.

    You must eat to stay in good health.

    Word by Word: You must to-eat for to-stay in good health.

    This shows the 'dev-' stem used with the 'vous' form.

Common Mistakes

  • Using 'ne pas devoir' to mean 'don't have to'.

    Tu ne dois pas venir si tu es fatigué.
    Tu n'as pas besoin de venir si tu es fatigué.

    In French, 'ne pas devoir' means 'must not' (prohibition). To say you 'don't have to' (lack of necessity), use 'ne pas avoir besoin de' or 'ce n'est pas la peine de'.

  • Spelling the first-person singular with an 'x' instead of an 's'.

    Je doix travailler.
    Je dois travailler.

    Learners often confuse 'devoir' with pouvoir (je peux) or vouloir (je veux). However, 'devoir' ends in -s.

  • Adding a preposition like 'de' or 'à' before the following verb.

    Je dois de partir.
    Je dois partir.

    Devoir is a modal verb and connects directly to the infinitive. Do not use 'de' or 'à' between them.

How It Connects

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devoir (présent)Level 1Irregular Verb Devoir (Must/to Have to)

Learn This First

To learn the present tense of 'devoir', you first need to be familiar with French subject pronouns (je, tu, il, etc.) and the basic sentence structure where the verb follows the subject. Familiarity with other irregular modal verbs is also helpful as they follow similar usage patterns.

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devoir