English uses just two words — "know" and "can" — where Russian uses three: знать, уме́ть, and мочь. Because the English mapping is loose, learners reach for знать far too often (saying things like зна́ю пла́вать for "I know how to swim," which is simply wrong). The three verbs carve up the territory cleanly once you see the logic: знать is about knowledge you hold, уме́ть is about a skill you have acquired, and мочь is about whether you are able or free to act right now. This page is the decision guide. For full conjugations, see мочь / смочь and знать / узна́ть.
The three meanings at a glance
| Verb | Core meaning | Takes… | Example |
|---|---|---|---|
| знать | to know (facts, info, a person, a language as knowledge) | a noun / embedded clause | Я зна́ю отве́т. |
| уме́ть | to know how, to have a learned skill | an imperfective infinitive | Я уме́ю води́ть. |
| мочь | to be able / free / allowed to (this occasion) | an infinitive | Я могу́ отвезти́ тебя́. |
The decision flowchart
- Is the object a fact, a piece of info, a person, or a language treated as knowledge? → знать.
- Is it a learned skill — "know how to" do something? → уме́ть
- imperfective infinitive.
- Is it about being able / free / allowed to do something on this occasion (circumstances, permission, capacity)? → мочь
- infinitive.
Case-by-case
знать — facts, information, people, languages-as-knowledge
Use знать for something you hold in your head: an answer, an address, a fact, a person you're acquainted with, or a language seen as a body of knowledge (words, rules — not the act of speaking).
Ты не зна́ешь, во ско́лько начина́ется фильм?
Do you happen to know what time the film starts? — знать + embedded question (information).
Я зна́ю э́тот реце́пт наизу́сть.
I know this recipe by heart. — знать + a thing held in the head.
Ты зна́ешь ру́сский?
Do you know Russian? — a language as a body of knowledge → знать.
уме́ть — a learned skill ("know how to")
Use уме́ть for an ability you acquired by learning or practice: driving, swimming, cooking, speaking a language. It is always followed by an imperfective infinitive, because a skill is an open-ended capacity, not a single completed act.
Я уме́ю води́ть, но давно́ не сади́лся за руль.
I can drive, but I haven't been behind the wheel in ages. — a learned skill → уме́ю + води́ть.
Она́ уме́ет гото́вить настоя́щий борщ.
She knows how to cook real borscht. — acquired skill → уме́ет + гото́вить.
Ты уме́ешь говори́ть по-ру́сски?
Can you speak Russian? — the SKILL of speaking → уме́ешь говори́ть (compare знать ру́сский, the knowledge).
мочь — possibility, permission, being free this time
Use мочь for whether you are able, free, or allowed to act on a particular occasion — a matter of circumstance, not training. Even if you can (have the skill), мочь asks whether conditions permit it now.
Я могу́ отвезти́ тебя́ домо́й — у меня́ как раз маши́на.
I can drive you home — I happen to have the car. — circumstance/possibility → могу́ + отвезти́.
Мо́жно войти́? — Да, мо́жете.
May I come in? — Yes, you may. — permission → the мочь / мо́жно family.
Извини́, сейча́с не могу́ говори́ть — перезвоню́.
Sorry, I can't talk right now — I'll call back. — not free at this moment → не могу́.
The key contrast: знать ру́сский vs уме́ть говори́ть
This pair shows the whole system. знать ру́сский = you possess the language as knowledge (vocabulary, grammar). уме́ть говори́ть по-ру́сски = you have the skill of producing it in speech. They are different claims, and English blurs both into "know/can speak Russian."
Он зна́ет ру́сский лу́чше меня́, но стесня́ется говори́ть.
He knows Russian better than I do, but he's shy about speaking. — знать (knowledge) vs the act of speaking.
And the three-way contrast on a single skill:
| Sentence | Verb | Why |
|---|---|---|
| Я зна́ю пра́вила пла́вания. | знать | the rules as information |
| Я уме́ю пла́вать. | уме́ть | the learned skill of swimming |
| Сего́дня я не могу́ пла́вать — у́хо боли́т. | мочь | can't on this occasion (circumstance) |
знать never means "know how"
A hard line worth burning in: знать cannot take an action infinitive to mean "know how." There is no зна́ю пла́вать, зна́ю води́ть, зна́ю гото́вить. The skill verb is always уме́ть. This is the single most common English-transfer error with these verbs.
Я уме́ю ката́ться на велосипе́де с пяти́ лет.
I've known how to ride a bike since I was five. — skill → уме́ю, never *зна́ю ката́ться.
The узна́ть shift: "find out / recognize"
Be aware that the perfective of знать, узна́ть, does not mean "to finish knowing" — the prefix shifts the meaning to "find out / come to know" and "recognize." It names the moment you enter the state of knowing. This is detailed on знать / узна́ть; the aspect logic behind such prefix shifts is on the aspect overview.
Я узна́л об э́том то́лько вчера́.
I only found out about it yesterday. — узна́ть = 'find out', the moment of coming to know.
Я тебя́ не сра́зу узна́л — ты постри́гся!
I didn't recognize you at first — you've cut your hair! — узна́ть = 'recognize'.
Common Mistakes
❌ Я зна́ю пла́вать.
Wrong — 'know how to' is a learned skill → уме́ть. знать never takes an action infinitive.
✅ Я уме́ю пла́вать.
I can swim. — skill → уме́ю.
❌ Ты уме́ешь, во ско́лько начина́ется фильм?
Wrong — this is information, not a skill → знать: Ты зна́ешь, во ско́лько…
✅ Ты зна́ешь, во ско́лько начина́ется фильм?
Do you know what time the film starts? — information → знать.
❌ Я уме́ю отвезти́ тебя́ сейча́с.
Wrong — this is about being free/able on this occasion, not a skill → мочь: Я могу́ отвезти́…
✅ Я могу́ отвезти́ тебя́ сейча́с.
I can give you a lift now. — possibility/circumstance → могу́.
❌ Ты зна́ешь говори́ть по-ру́сски?
Wrong — the skill of speaking is уме́ть говори́ть; зна́ешь would need a noun (зна́ешь ру́сский).
✅ Ты уме́ешь говори́ть по-ру́сски?
Can you speak Russian? — skill → уме́ешь говори́ть.
❌ Вчера́ я знал э́ту но́вость (meaning: I learned it).
Wrong — to come to know a piece of news is узна́ть: Вчера́ я узна́л… знал = was already in the state of knowing.
✅ Вчера́ я узна́л э́ту но́вость.
Yesterday I found out this news. — узна́ть = find out.
Key Takeaways
- знать = knowledge you hold — facts, information, a person, a language as a body of knowledge (зна́ю отве́т, зна́ю ру́сский). Takes a noun or an embedded clause, never an action infinitive.
- уме́ть = a learned skill, "know how to" (уме́ю води́ть, уме́ю пла́вать). Always + imperfective infinitive.
- мочь = able / free / allowed on this occasion — circumstance, possibility, permission (могу́ отвезти́ тебя́; не могу́ говори́ть).
- The diagnostic pair: зна́ешь ру́сский (knowledge) vs уме́ешь говори́ть (skill).
- знать never means "know how" — no зна́ю пла́вать. And its perfective узна́ть means "find out / recognize," not "finish knowing."
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- Смочь and the modal use of МочьB1 — Complete conjugation-and-usage reference for the modal pair мочь (imperfective) / смочь (perfective) 'to be able, can'. The irregular present with its г↔ж alternation (могу́, мо́жешь, мо́гут), the past мог/могла́, the perfective future смогу́/смо́жешь for 'manage to', the absence of an imperative, and the key contrast between мог (general ability) and смог (managed on a specific occasion).
- Знать / Узнать (know vs find out / recognize)A2 — Complete conjugation-and-usage reference for знать / узна́ть — a pair where the prefix changes the meaning, not just the aspect: imperfective знать (зна́ю, регуляр) means 'to know (a steady state)', while perfective узна́ть (узна́ю, узна́ешь, узна́ют) means 'to come to know, to find out' and 'to recognize' (Я тебя́ не узна́л 'I didn't recognize you'). Covers accusative and о + prepositional government.
- Verbal Aspect: The Big PictureA2 — Aspect is the spine of the Russian verb: nearly every verb belongs to a pair — imperfective (process, repetition, general fact) and perfective (a single completed whole with a result). This page explains the pair, the consequences for the tense system (perfectives have no present), and why you must decide 'process or result?' before you even pick a tense.
- Идти vs Ходить (and the Motion-Verb Choice)A2 — A decision guide for the unidirectional/multidirectional split across all the basic motion pairs. One question settles it: is this ONE trip in a single direction (now or planned) → идти́ / е́хать / лечу́, or REPEATED, round-trip, or general motion → ходи́ть / е́здить / лета́ю? Covers 'going to school now' (иду́) vs 'go every day' (хожу́), the round-trip past (ходи́л = went and came back) vs шёл (was on the way), flying to Paris tomorrow (лечу́) vs often fly (лета́ю), and general truths (пти́цы лета́ют, уме́ю пла́вать).