English leans on one little word, "can," for three quite different ideas: I can swim (ability), it can rain in April (possibility), can I leave? (permission). Czech does not let you off so lightly. The closest single verb is moci / moct, but it covers only part of that ground, and the rest is shared out among umět and smět. This page is about meaning — when each sense of moci applies, how context tells them apart, and where you must reach for a different verb instead. (For the full conjugation, the h/ž stem alternation, and every register variant, see the dedicated reference on moci / moct.)
The forms, in one breath
You only need the present at your fingertips to follow this page. Colloquial Czech uses the ž-forms; formal writing keeps the older h-forms in the já and oni slots:
| já | ty | on/ona | my | vy | oni | |
|---|---|---|---|---|---|---|
| spoken (informal) | můžu | můžeš | může | můžeme | můžete | můžou |
| written (formal) | mohu | můžeš | může | můžeme | můžete | mohou |
Like every modal, moci is followed by a bare infinitive — the action it frames. Everything below is about which sense that frame carries.
Sense 1 — ability (being in a position to)
Moci expresses ability in the sense of circumstances allowing it — you are in a position to do something, nothing is standing in the way. This is "can" as able to right now, not "can" as trained skill (that second one is umět, and the contrast matters — see below).
Můžu ti pomoct s těmi taškami?
Can I help you with those bags? (I'm free / able to — let me)
Po nemoci už zase můžu sportovat.
After my illness I can do sports again. (my body / the doctor now allows it)
Sense 2 — possibility (it might be so)
The same verb expresses epistemic possibility — "it may / might / could be the case." Here moci is not about anyone's ability; it weighs how likely something is. English splits this off as "may" or "might," but Czech keeps using moci.
Vezmi si bundu, může pršet.
Take a jacket, it might rain.
Může to být pravda, ale nejsem si jistý.
It could be true, but I'm not sure.
Každou chvíli může přijít, tak buď připravený.
He could arrive any moment, so be ready.
Sense 3 — permission (am I allowed?)
Third, moci asks for and grants permission — "may I?", "you're allowed to." In everyday speech this is the normal, unmarked way to ask leave; the more formal smět ("Smím?") sounds old-fashioned or very polite by comparison.
Můžu jít ven? Mám hotové úkoly.
Can I go out? I've finished my homework.
Tady se může parkovat zdarma o víkendu.
You can park here for free on weekends. (it's permitted)
In the past: "couldn't" and "could have"
The past tense uses the participle mohl / mohla / mohlo / mohli / mohly. Besides the plain "was able to," it carries the reproachful "could have" — an opportunity that existed but went unused.
Nemohl jsem přijít, měl jsem moc práce.
I couldn't come, I had too much work. (male speaker)
Mohla jsi mi to říct dřív!
You could have told me sooner! (reproach, to a woman)
In the conditional: the polite request
The conditional mohl/mohla bych... is the backbone of Czech courtesy — the natural way to make a request softer than a blunt Můžeš?. The participle agrees with the person doing the action, so it shifts for gender.
Mohl byste mi to ukázat ještě jednou?
Could you show me that once more? (to a man, formally)
Mohla bych dostat sklenici vody?
Could I get a glass of water? (a woman asking)
For the full toolkit of softened requests, see polite requests.
The big split: moci vs. umět vs. smět
This is the heart of the matter. English "can" maps onto three Czech verbs, and picking the wrong one is the most common modality error:
| Verb | Core idea | Example |
|---|---|---|
| moci / moct | circumstances allow it; be in a position to; be permitted | Nemůžu přijít. (something's in the way) |
| umět | a learned skill, know-how | Umím plavat. (I know how) |
| smět | explicit permission / prohibition | Smím vstoupit? (am I allowed?) |
One sentence shows the moci/umět split cleanly — the same person, two different "cans":
Umím řídit, ale teď nemůžu — pil jsem.
I can drive, but right now I can't — I've been drinking. (skill = umět; blocked circumstance = moci)
And smět sharpens permission to a yes/no of the rules — especially useful for diets, regulations, and children:
Smíš jíst sladké, nebo držíš dietu?
Are you allowed to eat sweets, or are you on a diet?
Common Mistakes
❌ Můžu mluvit česky, učím se rok.
Wrong verb — a learned skill takes umět, not moci.
✅ Umím trochu česky, učím se rok.
I can speak a little Czech, I've been learning for a year.
❌ Můžu mít účet, prosím?
Wrong verb — 'Can I have...?' in a café uses dostat (to get), not mít (to possess).
✅ Můžu dostat účet, prosím?
Can I get the bill, please?
❌ Děti, tady nemůžete běhat. (intending: it's forbidden)
Ambiguous — nemůžete can be read as 'you're unable'; for a clear ban use nesmět.
✅ Děti, tady nesmíte běhat.
Kids, you mustn't run here.
❌ Může být to pravda.
Wrong word order — the clitic 'to' must take second position, before být.
✅ Může to být pravda.
It could be true.
Key Takeaways
- Moci / moct covers three senses: ability (in a position to), possibility (might be so), and permission (allowed to).
- It takes a bare infinitive; spoken můžu... můžou, formal mohu... mohou.
- Past mohl/mohla also means "could have" (a missed chance); conditional mohl/mohla bych is the polite request.
- English "can" splits three ways: moci (circumstance), umět (skill), smět (permission) — and the negatives nemůžu / neumím / nesmím mean three different things.
Now practice Czech
Reading grammar gets you part of the way. The exercises are where it sticks — free, no signup needed.
Start learning Czech→Related Topics
- moci / moct — can, to be able toA1 — Full conjugation of the modal verb moci/moct (can), its h/ž stem alternation, the literary versus colloquial forms, and how it differs from umět and smět.
- umět vs moci vs znátB1 — Distinguishing 'know how to', 'be able to', and 'be acquainted with'.
- smět — May, Be AllowedB1 — How to use smět for permission and, crucially, its negative nesmět for prohibition — the form English speakers most often get wrong.
- Choosing moci, umět, znát, or vědětB1 — Distinguishing four verbs English collapses into 'can' and 'know'.
- Conditional for Polite RequestsA2 — How Czech builds politeness into the grammar itself — chtěl bych, mohl byste, prosil bych — so that asking with the conditional, not just adding 'please', is what makes a request courteous.