Devoir vs avoir besoin de to express "to need to"

Look at these two sentences expressing the idea of "need": 

J'ai besoin d'aller faire les courses avant le dîner.
I need to go shopping before dinner.

Je dois aller faire les courses avant dîner.
I need to go shopping before dinner.

Devoir + [infinitif] primarily means must [do] / have to [do], but in some cases it can be used as need to [do].

See Conjugate devoir in Le Présent (present tense)

Avoir besoin de + [infinitif] always means need to [do], as it literally means "to have need of".

See Avoir besoin de = To need

 

As for expressing to need [something], it will always be avoir besoin de [quelque chose] :  

Elle a besoin d'aide.
She needs help.

Tu as besoin d'argent.
You need money.

ATTENTION: 

Devoir [quelque chose] has a completely different meaning = to owe [something].
It can never mean to need [something].

Tu dois de l'argent.
You owe money.

Patrick me doit une faveur.
Patrick owes me a favour.


Special cases
:
"needing to go to the toilet"

As stated above, you can use either avoir besoin de or devoir in that case, but you could also use avoir envie de (= to feel like) in this specific case : though it can sound a bit "whimsical", it's perfectly colloquial here!

Mon fils doit aller aux toilettes.
My son needs to go to the toilet.

Mon fils a besoin d'aller aux toilettes.
My son needs to go to the toilet.

Mon fils a envie d'aller aux toilettes.
My son needs to go to the toilet.

"needing to throw up"

Another weird case is how to say you feel nauseous, need to throw up. In French, the most colloquial expression there is to use once again avoir envie de (= to feel like), though no one really ever "feels like" vomiting!

Arrête la voiture ! J'ai envie de vomir !
Stop the car! I feel nauseous!

See also Avoir envie de = To feel like, want to

 

Learn more about these related French grammar topics

Examples and resources

Patrick me doit une faveur.
Patrick owes me a favour.


J'ai besoin d'aller faire les courses avant le dîner.
I need to go shopping before dinner.


Arrête la voiture ! J'ai envie de vomir !
Stop the car! I feel nauseous!


Elle a besoin d'aide.
She needs help.


Mon fils a envie d'aller aux toilettes.
My son needs to go to the toilet.


Tu as besoin d'argent.
You need money.


Mon fils doit aller aux toilettes.
My son needs to go to the toilet.


Tu dois de l'argent.
You owe money.


Mon fils a besoin d'aller aux toilettes.
My son needs to go to the toilet.


Je dois aller faire les courses avant dîner.
I need to go shopping before dinner.


Q&A Forum 7 questions, 11 answers

Salut a tous, c'est moi encore!

How do I know when it is appropriate to say   d'argent  or  de l'argent

diner   or   le diner?

Asked 4 months ago
ChrisC1Correct answer

Hi Claudia, the usage of the definite article depends on several circumstances. I don't have a general rule handy to tell you. The one where it comes up most frequently is in sitations like this:

Mon voisin gagne beaucoup d'argent. -- My neighbor earns a lot of money.

Moi, je n'ai pas d'argent pour ce luxe. -- I don't have money for that luxury.

Il y a de l'argent à gagner ? -- Is there money to be made?

That's the case of the partitive article. Whenever there is a reference to a quantity (beaucoup in the first sentence, or even "no money" in the second sentence) you omit the definite article. If you are referring to money in general, as in the third example, you use the definite article.

You can read more about this here: https://www.lawlessfrench.com/grammar/partitive-article/

-- Chris.

 

Merci, vous etes tres gentil. Sorry about the accents. The computer is not set up for french yet.

Salut a tous, c'est moi encore!

How do I know when it is appropriate to say   d'argent  or  de l'argent

diner   or   le diner?

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SamA2

Hi, was this always in

Asked 4 months ago
AurélieKwiziq language super starCorrect answer

Bonjour Sam !

Indeed, we regularly review the order of lessons within and across levels, and move them across when deemed appropriate, which is what happened to this lesson :)

Bonne journée !

SamA2

Oops...

Was this always in A1 or has it been moved from a higher level? I've just seen it appear recently.

Thanks,Sam

Hi, was this always in

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MB1

Sorry again. The second sentence has only “dîner” without the “le”. Is there a reason for that?

Asked 9 months ago
CécileKwiziq language super starCorrect answer

Hi M

It is just a different way of saying the same thing:

Le dîner = dinner (noun)

Dîner = to have dinner (verb)

Hope this helps!

Sorry again. The second sentence has only “dîner” without the “le”. Is there a reason for that?

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MB1

Sorry was not finished.

Asked 9 months ago
CécileKwiziq language super star
answered...

Sorry was not finished.

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MB1

In the first example of the lesson, the sentence ends with “ le dîner”

Asked 9 months ago
CécileKwiziq language super star
answered...

In the first example of the lesson, the sentence ends with “ le dîner”

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Is "avoir à" a possible alternative to "devoir"

Is avoir à a possible alternative to devoir?

Can avoir à ever be used instead of devoir? For example j'ai à vous remercier instead of je dois vous remercier.
Asked 1 year ago
CécileKwiziq language super starCorrect answer

Hi William,

As the lesson points out 'devoir' can be both 'to have to' or 'to need to' something .

'Avoir à' is mostly used to indicate an idea of need rather than must as in :

Tu n'as pas à t'excuser = You don't need to apologise (in other words - it was not your fault)

Tu n'as pas à faire ça You don't need to do that ( or even: there's no need for you to do that

J'ai à faire = I have things to do (there are things I need to do

so it may be best to use 'devoir' or 'falloir' to convey the idea of 'must'.

Hope this helps!

 

I have heard "avaoir à" used in some specific context loke:

Tu n'as qu'à ranger ta chambre. -- You only have to clean up your room. 

 But I found a more comprehensive discussion here: https://www.reddit.com/r/French/comments/1urs43/avoir_à_vs_devoir/

Is "avoir à" a possible alternative to "devoir"

Is avoir à a possible alternative to devoir?

Can avoir à ever be used instead of devoir? For example j'ai à vous remercier instead of je dois vous remercier.

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Devoir

We are told that devoir can sometimes mean 'to need to [do]' yet only one example is given and no further explanation. In the example devoir is followed by a verb in the infinitive. Is that how devoir can be used?
Asked 1 year ago
CécileKwiziq language super starCorrect answer

Hi John,

This is quite subtle and it is when 'must' equals an imperative need to do something, rather than an obligation as the following examples will illustrate:

Je dois aller chez ma mère ce matin, elle ne va pas bien.

Je dois aller aux toilettes.

Je dois passer à la banque, je n'ai plus d'argent.

You would use 'devoir' rather than 'avoir besoin de' and as you have noticed it is followed by another verb in the infinitive.

Hope this helps!

Merci Cécile. Maintenant je comprends.

Devoir

We are told that devoir can sometimes mean 'to need to [do]' yet only one example is given and no further explanation. In the example devoir is followed by a verb in the infinitive. Is that how devoir can be used?

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