Могти (can / be able)

Infinitive (imperfective): могти́ — "to be able, can, may" Perfective partner: змогти́ — "to manage, to be able (on one occasion)" Type: an irregular modal verb (first conjugation, with a velar stem and a vowel alternation in the past)

могти́ is the verb you reach for hundreds of times a day: Чи мо́жу я…? "May I…?", Я не мо́жу "I can't." It expresses circumstantial ability — whether the situation, your schedule, your strength, or another person's permission allows an action — and it always takes an infinitive as its complement. That single fact already separates it cleanly from English, where "can" is a defective auxiliary with no infinitive of its own. Two irregularities make могти́ worth a dedicated page: the г→ж consonant change that runs through all six present forms (not just the first-person singular, as English speakers coming from Russian often assume), and the о/і vowel swap in the past — міг but могла́. Stress is marked on every form below.

Present tense — the г→ж mutation runs all the way through

The stem of могти́ ends in the velar г. Before the front vowel of the present endings this г softens to ж, and — unlike Russian мочь, where the mutation alternates — in standard Ukrainian the ж appears in every single person. There is no мо́гу form; it is always мо́жу.

The stress sits firmly on the stem (мо́-) in every present form — it never moves to the ending. A common trap for Russian speakers is to stress можу́ on the ending: in Ukrainian it is always мо́жу.

Past tense — the о/і alternation: міг but могла́

The past is built off the stem мог- with the usual gendered endings, but the masculine singular loses its vowel ending and the о raises to і in the resulting closed syllable: міг. As soon as a vowel ending is added (-ла, -ло, -ли), the syllable reopens and the о returns: могла́, могло́, могли́. This о↔і alternation is one of the signature features of Ukrainian — the same thing that gives ніч / но́чі and стіл / стола́.

Note the stress: the masculine міг is a stressed monosyllable (unmarked), but the feminine, neuter and plural all stress the ending — могла́, могло́, могли́. The perfective past зміг / змогла́ / змогло́ / змогли́ "managed to" follows the identical pattern.

Future tense — perfective simple vs imperfective compound

Aspect splits the future cleanly. The perfective змогти́ has no present meaning at all: its present-tense forms point to the future — я зможу́ means "I will be able / I'll manage." The imperfective могти́ uses the two ordinary imperfective futures: the analytic бу́ду + могти́ and the synthetic могти́му.

In practice the perfective зможу́ is by far the most common future, because "being able to do X" is usually a one-off, completable thing: Я зможу́ прийти́ за́втра "I'll be able to come tomorrow." The imperfective futures (бу́ду могти́, могти́му) describe an ongoing or repeated capacity and are much rarer — you can read more on the aspect in the future page.

Conditional — міг би / могла́ б "could, would be able"

The conditional is the past form plus the invariant particle би (or б after a vowel). This is the everyday way to soften a request or float a possibility — Ти міг би мені́ допомогти́? "Could you help me?" is far more polite than the bare present.

Imperative

The bare imperative of могти́ is rare — you don't normally order someone to "be able." What you do use constantly is the 3rd-person хай / неха́й form, "let him / let them," and the fixed politeness frame мо́жна (an impersonal "one may / it's allowed") which behaves like a modal of permission.

Participles and verbal adverbs

могти́ is light on non-finite forms. There is no usable passive participle (it is intransitive), and the active participle мо́жучий is (archaic / non-standard) — modern Ukrainian avoids -ючий active participles and prefers a relative clause (той, хто мо́же). The verbal adverbs do exist but are uncommon.

Key uses & case government

1. могти́ + infinitive — the only complement

могти́ takes a bare infinitive, never a noun object of its own: you "can do" something, not "can something." The aspect of that infinitive carries the meaning — perfective for a single completed act (мо́жу прочита́ти "I can read [it through]"), imperfective for an activity or process (мо́жу чита́ти "I can read / am able to read"). See infinitive complements.

2. могти́ for permission — "may I?"

Beyond physical ability, могти́ asks and grants permission: Чи мо́жу я зайти́? "May I come in?" In this sense it overlaps with the impersonal мо́жна ("Мо́жна зайти́?"), which drops the subject entirely and is the more casual choice.

3. Negation — не мо́жу, не міг

Negate by placing не before the verb; the governed infinitive stays as it is. Unlike many genitive-governing verbs, могти́ does not trigger a case change under negation, because its complement is an infinitive, not a noun. Я не мо́жу зрозумі́ти "I can't understand."

Common Mistakes

Key Takeaways

• могти́ = circumstantial ability / permission; вмі́ти = a learned skill. Don't translate every English "can" with могти́.
• Present (г→ж throughout): мо́жу / мо́жеш / мо́же / мо́жемо / мо́жете / мо́жуть — never мо́гу, always stem-stressed.
• Past (о/і alternation): міг (masc.) but могла́ / могло́ / могли́ — the vowel raises to і only in the closed masculine syllable.
• Future: perfective зможу́ / змо́жеш… carries the everyday future ("I'll be able to"); the imperfective бу́ду могти́ / могти́му is rarer.
• Complement: always a bare infinitive — могти́ never takes a noun object, so negation triggers no case change.
• Conditional міг би / могла́ б is the polite, softened way to ask "could you…?"