Correctly Use the Confusing French Pairs Bon vs. Bien

Young student
Il est bon étudiant / Il est bien comme étudiant. (He is a good student.). Catherine Delahaye/Getty Images

Bon and bien are often confused because they have somewhat similar meanings and they can both be adjectives, adverbs, or nouns. See the summary table at the bottom.

Adjectives

Bon is usually an adjective. It modifies a noun and means good, suitable, efficient, correct, useful, etc. Bien means good, moral, right, healthy, etc., and can only be used as an adjective with copular (state-of-being) verbs such as être.

Il est bon étudiant.
He is a good student.
Il est bien comme étudiant.
He is a good student.
J'ai passé une bonne soirée.
I had a nice evening.
Ça serait bien !
That would be good!
Il a bon cœur.
He has a good/kind heart.
Très bien !
Very good!
Ce timbre n'est pas bon.
This stamp is not valid.
Je suis bien partout.
I'm at ease anywhere.
Luc est bon pour le service.
Luc is fit for (military) service.
Ce n'est pas bien de dire ça.
It's not nice to say that.
Je le trouve bien.
I think it's nice.

Adverbs of Manner

Bien is usually an adverb. It means well or can be used to stress something. Bon, in the rare instances where it is used as an adverb, means good or pleasant.

J'ai bien dormi.
I slept well.
Il fait bon ici.
It's nice/pleasant here.
Il se porte bien.
He is in good health.
Il fait bon vivre.
It's good to be alive.
Je vais bien, merci.
I am well, thank you.
Il fait bon étudier.
It's good to study.
La radio ne marche pas bien.
The radio isn't working right.
Ça sent bon !
That smells good!
Je le vois bien souvent.
I see him quite often.
J'ai bien dit ça.
I *did* say that.

Nouns

Bon can be a noun that refers to any sort of important or official piece of paper: form, bond, coupon, voucher, etc. Bien means good in the general sense, and biens means goods (as opposed to services).

un bon à vue
demand note
le bien public
public good
un bon de caisse
cash voucher
le bien et le mal
good and evil
un bon de commande
order form
dire du bien de
to speak well of
un bon de livraison
delivery slip
faire du bien à quelqu'un
to do someone good
un bon de réduction
coupon
les biens d'un magasin
a store's goods
un bon du Trésor
Treasury bond
biens immobiliers
real estate
En résumé
Bon Bien
adjective good well
adverb nice well
noun form, bond good(s)