Focus on French Verbs: savoir

The French verb savoir most often means "to know." You can use it when you know a fact, have a piece of information, know the answer to a question, or know how to do something.

The construction after savoir helps show what kind of knowledge you are talking about. It can be followed by a noun, a clause, a question word, or an infinitive.

Conjugation

Savoir is an irregular verb. Its present-tense forms include je sais, nous savons, and ils savent. Its past participle is su.

The future and conditional use the stem saur-:

See savoir for all tenses and forms.

Savoir + noun: knowing information

Savoir can take a noun when the object represents a fact, answer, piece of information, or something that can be known:

The basic pattern is:

savoir + information

No preposition is required between savoir and the information known. This use is particularly common with words such as réponse, adresse, nom, date, and vérité.

Savoir que + clause

Use savoir que when what someone knows is expressed as a complete statement:

savoir que + clause

Savoir que presents the following information as something the subject knows.

Savoir + question word

Savoir commonly introduces an indirect question with words such as où, quand, pourquoi, comment, qui, and ce que:

These constructions are extremely common because savoir often describes having the answer to a question. A direct question such as Où est la gare ? can become Vous savez où est la gare ? when embedded after savoir.

Savoir + infinitive: knowing how to do something

Use savoir + infinitive to say that someone knows how to do something:

savoir + infinitive

French does not insert a word corresponding to English "how to" between savoir and the infinitive. The construction generally describes learned knowledge, ability, or knowing the method required to perform an action.

Savoir or pouvoir?

A sentence with savoir + infinitive says that someone knows how to perform an action:

It does not necessarily say whether the person is able to perform that action in the present circumstances. The knowledge or skill remains even when circumstances prevent the action. This distinction is useful because English "can" sometimes expresses both knowledge and practical ability, while French can be more explicit about the difference.

Je sais and je ne sais pas

Je sais and je ne sais pas are extremely common conversational expressions:

Je ne sais pas is often reduced in informal spoken French, but the full form remains the standard written form.

Je ne sais pas + question word + infinitive

When the subject of savoir would also perform the following action, French can use a question word followed by an infinitive:

savoir + question word + infinitive

Savoir si

Use savoir si when the information involves whether something is true or will happen:

savoir si + clause

Here, si introduces an indirect yes-or-no question.

Savoir bien

Bien savoir can emphasize that someone knows something well:

Je sais bien can also have a conversational force beyond simply describing the degree of someone's knowledge. Depending on context and tone, it can acknowledge something that the speaker already understands or has already been told.

Savoir par cœur

Savoir quelque chose par cœur means to know something by heart:

The expression indicates that something has been memorized well enough to recall without looking it up.

Savoir de quoi on parle

The construction savoir de quoi on parle means to know what one is talking about:

Here, de quoi belongs to the indirect question introduced by savoir. It is not a separate savoir de construction. The expression can indicate knowledge or experience with a particular subject.

À savoir

The expression à savoir is used to introduce a clarification, specification, or list. Depending on context, it can correspond to "namely," "that is," or "specifically":

This use is more common in formal or written French than in basic conversation. It is best learned as the fixed expression à savoir rather than as a general savoir + à construction.

Que je sache

The expression que je sache means as far as I know or to my knowledge:

The expression limits a statement to what the speaker currently knows. It is often used when the speaker does not want to claim absolute certainty. The form sache is the present subjunctive of savoir.

Autant que je sache

Autant que je sache is another common way to say as far as I know:

Like que je sache, the expression indicates that the statement is based on the speaker's available knowledge.

Va savoir !

The expression Va savoir ! can mean "Who knows!" or "How should I know!", depending on context and tone:

The expression does not literally tell someone to go and acquire information. It is an idiomatic way of saying that the answer is unknown or difficult to determine.

Common expressions with savoir

Several useful constructions and expressions use savoir:

• savoir quelque chose — to know something
• savoir que + clause — to know that…
• savoir où / quand / pourquoi / comment… — to know where / when / why / how…
• savoir si + clause — to know whether…
• savoir + infinitive — to know how to do something
• savoir quoi faire — to know what to do
• ne pas savoir — not to know
• savoir par cœur — to know by heart
• je sais bien — I know / I know very well
• à savoir — namely, that is
• que je sache — as far as I know
• autant que je sache — as far as I know
• va savoir ! — who knows!

Common mistakes with savoir

Don't add comment before an infinitive

To say that someone knows how to do something, use:

The ordinary construction is savoir + infinitive. French does not need comment to reproduce the English words "how to."

Don't add a preposition before the infinitive

There is no à or de between savoir and the infinitive.

Use si for an indirect yes-or-no question

Here, si means "if/whether" and introduces the information being asked about.

Keep the word order of an indirect question

Once the question becomes part of a sentence introduced by savoir, it uses indirect-question structure.

Remember the irregular future stem

The future is built on saur-:

The conditional uses the same stem (je saurais). This stem cannot be predicted simply by keeping the infinitive savoir unchanged.

Savoir vs connaître

English uses "know" for both verbs, but French distinguishes the type of knowledge.

Use savoir for facts, information, and knowing how to do something:

Use connaître for familiarity with a person, place, subject, or thing:

A useful contrast is savoir + clause or infinitive versus connaître + noun.

Savoir vs croire

Savoir presents something as known or as information the speaker has:

Croire presents something as a belief, opinion, or assumption:

The distinction is one of certainty and epistemic stance rather than grammar alone.

Related verbs

The most important patterns are savoir + information, savoir que, savoir + question word, savoir si, and savoir + infinitive.

From learning to practice

Je ne sais pas and Tu sais où… ? are among the first phrases you need in French — at a ticket counter, on the street, in class. For skills, Je sais nager never takes comment or à: the infinitive follows savoir directly. When someone asks if you know a person or a neighborhood, that is connaître, not savoir; mixing them up is one of the most common errors English speakers make.