In French, verbs change their form to show mood, tense, and to match the subject in person and number. Like in Latin grammar, all the different forms of a French verb are called its conjugation.

Stems and endings

French verbs have many simple forms, which are made up of two parts: the stem (or root) and the ending (inflection). The stem shows which verb it is, while the ending shows the verb's tense (like present, past, or future), mood, and who is performing the action (such as I, you, he, or they). Some endings can match more than one tense, mood, or subject. In certain parts of the second conjugation, there is also a small part called "-iss-" between the stem and ending. This part comes from an old language rule called an inchoative suffix.

Verb conjugations are often used with subject pronouns (like I, you, he, or they) to make it clear who is doing the action. It can be hard to tell the stem from the ending in some irregular verbs, such as avoir (to have), aller (to go), dire (to say), être (to be), faire (to do/make), pouvoir (can), savoir (to know), valoir (to be worth/cost), and vouloir (to want). These verbs do not always have a clear stem and change in different ways.

In the first two conjugations, the stem usually stays the same. However, in the third conjugation, the stem often changes, even between different subjects in the same tense. Despite these changes, the stem itself is not usually shortened or removed. For example, verbs ending in "-guer" or "-quer" keep the "-gu-" or "-qu-" throughout their conjugations, even if French spelling rules might suggest simplifying them to "-g-" or "-c-".

Although the stem is not usually shortened, letters can be added when needed. Some stems change their spelling (not considered irregular) to keep the correct pronunciation. The ending is a suffix that shows the verb's tense, mood, and subject. Except for a few very irregular verbs (like avoir, être, aller, and faire), each tense and mood has a set of six endings (one for each subject). These endings must stay the same for all verbs in a group or subgroup during a specific tense. Even if spelling rules might allow changes, the endings are not modified.

Formation of simple tenses active

These tenses are not formed with an auxiliary verb, and their formation is discussed in the following section. A verb is usually named by its present infinitive (Infinitif présent). From this infinitive, conjugations can be grouped into three categories. Note that the auxiliary verbs être and avoir, even though they might naturally belong to the third conjugation, are traditionally classified separately.

The present indicative is the form of the verb used to describe actions happening now. For example, Je parle means "I speak" or "I am speaking." The stem of the present indicative is not always regular and may vary, especially in the third conjugation. There are three main sets of endings for this tense.

The imperfect indicative is a past tense used to describe actions that continue into the present or are repeated. For example, je parlais means "I was speaking" or "I used to speak." It may also be used when an action is interrupted, such as je parlais avant que tu m'arrêtes, meaning "I was speaking before you stopped me." In modern language, this tense is used only in formal writing, often for historical events or in novels. It has been replaced by the passé composé in other contexts. The stem of the past historic tense is not always regular but remains the same for a single verb. There are four sets of endings for this tense.

The future tense endings match the present indicative of the verb avoir. These endings are always regular: -ai, -as, -a, -ons, -ez, -ont, pronounced /e, a, a, ɔ̃, e, ɔ̃/. Some verbs have a double r in their future forms, such as envoyer (j'enverrai), mourir (je mourrai), and courir (je courrai).

The conditional tense endings match those of the imperfect indicative. These are also regular: -ais, -ais, -ait, -ions, -iez, -aient, and in rare cases, -it, pronounced /ɛ, ɛ, ɛ, jɔ̃, je, ɛ/. Sometimes the past imperfect subjunctive is used instead of the present conditional. This form is called the present conditional second form (Conditionnel présent deuxième forme). The regular conditional is then called the present conditional first form (Conditionnel présent première forme). This second form is now very rare, used only in sentences starting with Même si or the phrase fût-ce. The past conditional second form (Conditionnel passé deuxième forme) is still commonly used in literature.

The imperfect subjunctive is always formed from the past historic. If the past historic does not exist (for defective verbs), the imperfect subjunctive also does not exist. The stem of the imperfect subjunctive is taken from the second person singular of the past historic, except in the third person singular, where the final -s is replaced with a circumflex over the preceding vowel. The endings are always: -se, -ses, -ˆt, -sions, -siez, -sent, pronounced /s, s, -, sjɔ̃, sje, s/.

The imperative is used only in three persons: second singular, first plural, and second plural. The subject pronoun is always omitted in this form.

The present participle (le participe présent) is typically formed by replacing -ons with -ant in the first-person plural of the present indicative. Exceptions include avoir (ayant), être (étant), and savoir (sachant). In all cases, the present participle ends in -ant.

The gerundive (le gérondif) is formed by adding the preposition en to the present participle. For example, the gerundive of faire is en faisant.

The present participle and gerundive are invariable; they do not change form to agree with other parts of a sentence.

Past participles, unlike present participles and gerundives, may change to show gender and number by adding -e and -s, like a normal adjective. For example, un fruit confit, une poire confite, des fruits confits, and des poires confites. This inflection occurs only with transitive verbs and certain reflexive verbs.

The plain (masculine singular) form of a past participle may end in -é (1st group verbs, such as naître [né], être [été], and aller [allé]), -i (2nd group verbs, such as sortir [sorti] and partir [parti]), -u (verbs like entendre [entendu], boire [bu], and lire [lu]), -is (verbs like mettre [mis] and prendre [pris]), -us (verbs like inclure [inclus] and reclure [reclus]), -it (verbs like maudire [maudit] and dire [dit]), -t (verbs in -indre, such as peindre [peint

Defective verbs

Some verbs are missing certain forms. They do not have forms for all tenses, moods, or persons. These verbs are called defective. Examples include: