meilleur vs mieux

Summary

Both translate English "better", but meilleur is the irregular comparative of the adjective bon (and agrees with its noun), while mieux is the irregular comparative of the adverb bien (and never changes). *plus bon and *plus bien do not exist.

Explanation

English hides two different French words behind one label, "better". The split follows the grammar of the base word: bon ("good") is an adjective and bien ("well") is an adverb, and French forms their comparatives irregularly. Adjectives never take *plus bon; instead bon → meilleur. Adverbs never take *plus bien; instead bien → mieux.

meilleur is an adjective, so it qualifies a noun and agrees with it in gender and number: un meilleur livre, une meilleure idée, de meilleurs résultats, les meilleures notes. It answers "a better what?" and pairs with être describing a thing: ce vin est meilleur (this wine is better). The superlative simply adds the article: le meilleur, la meilleure (the best).

mieux is an adverb, so it modifies a verb (or a whole clause) and is invariable — it has one spelling for everyone: il chante mieux (he sings better), elle va mieux (she is doing better), ça marche mieux comme ça (it works better this way). It answers "do something how?" Its superlative also just adds the article: le mieux (best, as in c'est ce que je fais le mieux).

A clean test decides it. If the "better" attaches to a noun (better + noun) or is an attribute of a thing after être meaning "of higher quality", use meilleur and make it agree. If the "better" describes how an action is performed (a verb, well → better), use the invariable mieux. Compare: C'est un meilleur joueur (a better player — noun) but Il joue mieux (he plays better — verb).

The traps for English speakers are three. First, inventing *plus bon or *plus bien: both are wrong; the words are already comparative. Second, forgetting agreement on meilleur (*une meilleur idée instead of une meilleure idée). Third, swapping the two because English uses the same word — writing *il chante meilleur (should be mieux) or *un mieux livre (should be meilleur). Bien exists as an adjective only in a fixed evaluative sense (une personne bien), which does not affect this comparative pair.

Rule of thumb: describing a noun or a thing's quality → meilleur (and agree it); describing how an action goes → mieux (invariable). If you can replace the idea with "good", you want meilleur; if you can replace it with "well", you want mieux — and never *plus bon / *plus bien.

Examples

Ce restaurant est meilleur que l'autre. — This restaurant is better than the other one. (Attribute of a thing after être, higher quality -> adjective meilleur.)

Elle a eu une meilleure note que moi. — She got a better grade than me. (meilleure agrees (feminine) with the noun note.)

Aujourd'hui, je me sens mieux. — Today I feel better. (Modifies the verb (how one feels) -> invariable mieux.)

Il joue mieux que son frère. — He plays better than his brother. (Describes the action of playing -> mieux, never *meilleur.)

C'est le meilleur film de l'année. — It's the best film of the year. (Superlative adjective: le meilleur + noun.)

C'est ce que je fais le mieux. — It's what I do best. (Superlative adverb le mieux modifying the verb faire.)

Common mistakes

Related rules

• bon vs bien
• Comparatives (plus / moins / aussi … que)
• Superlatives (le/la/les plus / moins …)
• Adverbs: formation and position