What is the difference between oui and si?

Oui is the ordinary yes. Si is the yes that contradicts a negative question or statement, as in: you don't like chocolate? Yes I do.

Is oui formal or informal?

Neither. Oui is neutral and works with anyone.

French · phrasebook

How to say yes in French

Yes in French is oui. French also has a second yes, si, with one job: it contradicts a negative question or statement. English has no word for that, which is why learners miss it.

Aurélien CuvelierSep 19, 2026

oui

yes

anyone

The ways to say it

oui

yes

anyone

yes (answering a negative question)

anyone

How to use it

Look at the first exchange. The question is negative: you don't like chocolate? Answering oui would be unclear, because it could confirm the negative. Si settles it: yes I do. Whenever the sentence you are answering contains a negation and you disagree with it, the answer is si.

Everywhere else, the answer is oui: in a shop, at work, with friends. It is neutral in register, so it never needs a formal or an informal version.

Watch out

Si as a yes only ever answers a negative. The same spelling also means if, inside a sentence. At the start of a reply, after a negative question, it is the yes.

In a real conversation

Each exchange is a line and its reply. Greyed letters are written and not pronounced. A tie marks a liaison, with the sound you hear under it. A label under a verb names its tense when it is not the present.

Tu n'aimes pas le chocolat ?You don't like chocolate?Si, j'adore le chocolat !Yes, I love chocolate!

Bonjour, vous avez encore des baguettes ?Hello, do you still have baguettes?Oui, il en reste deux.Yes, there are two left.

Questions people ask

What is the difference between oui and si?: Oui is the ordinary yes. Si is the yes that contradicts a negative question or statement, as in: you don't like chocolate? Yes I do.
Is oui formal or informal?: Neither. Oui is neutral and works with anyone.

More French phrases

Each one with its tu and vous forms, its register and real exchanges.

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Written by

Aurélien Cuvelier Founder, NuanceDeck

Aurélien Cuvelier builds NuanceDeck: the app, and the verification pipeline behind its dictionary. Every entry is grounded in the official TORFL lexical minimum and a 20,000-word frequency corpus, and every example sentence passes a certification review before it ships.

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