Savoir: Complete Paradigm Reference

This is the complete paradigm reference for savoir — every simple tense, every compound tense, every mood, including the literary forms (sus, sût, sussent, eût su) that you will rarely produce but must recognize when reading. The everyday treatment of savoir — knowing facts, knowing how to, the contrast with connaître, the aspectual shift in the passé composé (j'ai su = "I found out") — lives at verb-reference/savoir. This page is for the moments when you need to look up a form, including the obscure ones.

Savoir is a 3rd-group irregular verb whose paradigm splits across four distinct stems that you must learn separately: sai- (présent sg), sav- (présent pl, imparfait, infinitive), sau- (futur, conditionnel), and sach- (subjunctive, imperative, present participle). The passé simple takes a fifth pattern, su-/sû-, shared with the participle. This makes savoir one of the most fragmented paradigms in French — but each stem is internally regular, so once the stems are memorized, each tense is predictable.

Etymology: Latin sapere

French savoir descends from Latin sapere, originally meaning "to taste, to perceive by taste" — the metaphor "to know" emerged in Vulgar Latin. The Spanish cognate saber and Italian sapere preserve the same meaning. The Latin p lenited to /v/ in French (the sav- stem of savons, savais, savoir), but in some forms — notably the futur — the p dropped entirely, giving sau- (saurai descends from sapēre habeo).

The subjunctive stem sach- descends from a Latin form sapiam with the palatalization pi → /tʃ/ → /ʃ/, written ch in modern French. This is why the subjunctive looks so different from the indicative: it preserves a Latin sound change that the indicative did not undergo.

Simple tenses: complete paradigms

Présent de l'indicatif

Two stems: sai- (1sg, 2sg, 3sg) and sav- (1pl, 2pl, 3pl). The 3sg sait and the 3pl savent both end in -t/-ent but the singular drops the consonant of the plural stem.

The forms sais, sais, sait are all pronounced /sɛ/ — three homophones distinguished only in writing.

Imparfait

Built on the sav- stem (from nous savons) plus the regular imparfait endings. Fully predictable.

For "I knew" in past narration, the imparfait je savais is the default — savoir in passé composé (j'ai su) takes on the punctual meaning "I found out / learned," not "I knew." This aspectual shift is one of the most important details about savoir.

Passé simple (literary)

Stem su- (the same vowel as the participle su), pronounced /y/ throughout. Used in literary writing — almost never spoken.

The circumflex on sûmes and sûtes is obligatory — it marks the long vowel and historically descends from a lost -s- (medieval su(s)mes). The 1990 spelling reform makes the circumflex optional on i and u in many words, but it is kept on the 1pl/2pl of the passé simple and subjonctif imparfait to disambiguate from other forms.

In the passé simple, savoir takes on the same punctual "find out" meaning that the passé composé does in modern speech. Il sut la vérité = "he learned/discovered the truth" (literary).

Futur simple

Stem sau- (irregular — the p of Latin sapere dropped entirely here, giving a stem that shares no obvious connection with the infinitive savoir). Endings are the regular futur endings.

Conditionnel présent

Same stem sau- as the futur, with imparfait endings.

The conditional has a special idiomatic use with negation: je ne saurais (instead of je ne pourrais) is a formal, slightly archaic way of saying "I cannot, I would not be able to." Je ne saurais vous dire = "I couldn't tell you / I wouldn't know how to say" (formal).

Subjonctif présent

Stem sach- (irregular — does not derive from any indicative form). This stem descends from a different Latin form (sapiam) than the indicative sav- and the futur sau-, which is why it looks so different.

Notice that savoir keeps the sach- stem in all six persons of the subjunctive — unlike many irregular verbs (aller, vouloir, prendre, venir) that have a strong/weak split between singular and plural. Savoir is uniformly sach- in the subjunctive.

Subjonctif imparfait (literary)

Built on the su- stem of the passé simple, with the standard subjunctive-imparfait endings. Used almost exclusively in literary writing.

The 3sg sût takes a circumflex — without it, the form would be indistinguishable from the passé simple 3sg sut (also pronounced /sy/). The circumflex on sût is the orthographic signal that the form is the subjonctif imparfait, not the passé simple. This disambiguating role of the circumflex is the same one it plays in fût (vs fut), eût (vs eut), and vînt (vs vint) — all 3sg subjunctive imparfait forms that would otherwise collide with their passé simple counterparts.

Impératif

Three forms, taken from the subjunctive stem sach-. The imperative of savoir is rare but not extinct — it occurs in fixed expressions and elevated style with the meaning "be aware that, take note that."

Participles and gérondif

The present participle sachant preserves the subjunctive stem sach- — unusual, since most present participles derive from the nous form of the present (nous savons would have given savant, which exists as a noun meaning "scholar" but not as the active participle of the verb). This split is historical: French preserves sachant as the verbal participle and savant as a noun derived from the same Latin root. En sachant — "by knowing, knowingly" — uses the verbal form.

Compound tenses: complete paradigms

Savoir uses avoir as auxiliary in compound tenses. The participle su never agrees with the subject; it agrees only with a preceding direct object.

A crucial aspectual point: in compound tenses, savoir shifts meaning from "to know" to "to find out, to learn" (the "ingressive" meaning). J'ai su la nouvelle ce matin = "I found out the news this morning," not "I knew the news this morning." For "I knew," use the imparfait je savais. This aspectual shift is identical to the one in connaître (j'ai connu = "I met for the first time") and is one of the trickiest details about French past tenses.

Passé composé

avoir (présent) + su

A second meaning of j'ai su is "I managed to / I was able to" — almost like j'ai pu but emphasizing skill rather than circumstance: j'ai su garder mon calme = "I managed to keep my cool."

Plus-que-parfait

avoir (imparfait) + su

Passé antérieur (literary)

avoir (passé simple) + su

Futur antérieur

avoir (futur) + su

Conditionnel passé

avoir (conditionnel) + su

Subjonctif passé

avoir (subjonctif) + su

Plus-que-parfait du subjonctif (literary)

avoir (subjonctif imparfait) + su

Pronunciation notes

Three points are worth memorizing.

1. The participle su and the entire passé-simple paradigm are pronounced /y/. Su, sus, sut, sûmes, sûtes, surent all use the /y/ vowel — never the /u/ of nous or the /ø/ of peu.

2. The subjunctive stem sach- is /ʃ/, the same sound as English sh. Don't pronounce it as /k/ (a common Anglophone error). Sache /saʃ/, sachons /sa.ʃɔ̃/.

3. The futur stem sau- is /so/, with an open /o/. Saurai /so.ʁe/, saurions /so.ʁjɔ̃/. The vowel is the same as in taupe, faute.

Comparison with English

Three friction points worth restating in a paradigm reference.

1. Passé composé means "found out," not "knew." J'ai su = "I learned, I found out, I came to know." For "I knew" (ongoing past state), use the imparfait je savais. This aspectual shift has no English parallel — knew in English doesn't change to a different word for the punctual meaning.

2. The subjunctive sache is invariant across all six persons. Most irregular subjunctives have a strong/weak split (aille / allions, vienne / venions); savoir is uniformly sach-, which makes it slightly easier to learn once you know the stem.

3. The conditional je ne saurais is a formal way of saying "I cannot." This idiom replaces je ne pourrais in elevated speech and writing, especially with verbs of cognition: je ne saurais dire, je ne saurais expliquer, je ne saurais croire. It's a marker of polite, slightly archaic register.

Common Mistakes

Mistake 1: Using j'ai su for "I knew" instead of "I found out."

Mistake 2: Pronouncing sache with /k/ instead of /ʃ/.

Mistake 3: Using savoir where connaître is required.

Mistake 4: Forming the futur from the infinitive directly.

Mistake 5: Using que tu sais instead of que tu saches.

Key takeaways

Savoir has four distinct stems that you must learn as separate paradigms: sai- (présent sg), sav- (présent pl, imparfait, infinitive), sau- (futur, conditionnel), and sach- (subjunctive, imperative, present participle). The passé simple and participle add a fifth pattern, su-/sû-. Each stem is internally regular, but the four (or five) stems share no common surface root.

The subjunctive sache is uniformly sach- across all six persons — no strong/weak split. This makes the subjunctive of savoir slightly more predictable than that of aller, vouloir, prendre.

In compound tenses, savoir takes avoir as auxiliary and shifts meaning from "to know" to "to find out, to learn." J'ai su = "I found out"; for "I knew," use je savais. The same aspectual shift applies in the passé simple (je sus = "I learned").

The circumflex on sût (subjonctif imparfait 3sg) is obligatory and is the only orthographic distinction from the passé simple 3sg sut — without the diacritic the two forms would be identical in spelling. The same disambiguating circumflex appears on eût, fût, vînt and the entire 3sg subjonctif imparfait paradigm of irregular verbs.

The participle present sachant uses the subjunctive stem rather than the indicative — a historical preservation that distinguishes the verbal participle from the noun savant ("scholar") derived from the same Latin root.

This page is the paradigm reference. For the everyday usage — knowing facts vs. knowing how to, the savoir/connaître contrast, the aspectual meaning shift in the passé composé — see verb-reference/savoir.