dělat / udělat — to do, to make

dělat / udělat ("to do, to make") is one of the first verbs every Czech learner meets, and it is worth meeting properly, because it is two verbs, not one. dělat is the imperfective member of the pair and udělat is the perfective member — same meaning, but a different way of looking at the action. dělat is also the textbook model for the entire -á- conjugation class, so once you can run through its endings, you can conjugate hundreds of regular verbs the same way.

One verb, two aspects

English uses a single verb ("do") and adjusts the surrounding tense and context to say whether an action is ongoing or finished. Czech bakes that distinction into the verb itself. dělat presents an action as a process — happening, repeating, in progress, without a built-in endpoint. udělat (literally dělat plus the prefix u-) presents the same action as a single completed whole, viewed from its result.

This is the heart of Czech aspect, and dělat/udělat is the cleanest possible illustration of it. For the full picture, see what is aspect and the aspect pairs overview.

Present tense — dělat (imperfective)

Drop the -t of the infinitive to get the stem děla-, then add the -á- class endings. The vowel is long (á) everywhere except the third-person plural.

Note the -ají in the third-person plural: this is the single slot in the paradigm where the stem vowel is short (dělají), while every other form keeps the long á (dělám, děláš, dělá, děláme, děláte). A common slip is to drag the long vowel in by analogy and produce dělájí, or to drop down to the bare colloquial dělaj — the standard written form is dělají. Czech has no present progressive (no "am doing" auxiliary), so dělám alone covers both "I do" and "I am doing." See present tense, no progressive.

Present-tense forms of udělat = future

Here is the point that trips up every beginner: a perfective verb has no real present tense. You cannot be "in the middle of completing" something — completion is a point, not a process. So the present-tense endings on udělat do not describe now; they describe a single completed action in the future.

See the perfective present is a future for why this works the way it does.

The aspect minimal pair, side by side

Because the two verbs differ only in aspect, putting them next to each other shows the contrast in its purest form.

Past tense — both members

The past is built from the l-participle plus the present-tense auxiliary být in the first and second persons (and nothing at all in the third). The participle agrees in gender and number with the subject. For the full mechanics, see forming the past tense.

The aspect contrast carries straight into the past. Imperfective past describes an action as it unfolded or repeated; perfective past reports it as a completed fact.

Future tense — the two strategies

This is where the asymmetry of the pair becomes practical. The perfective future is just the present-form endings on udělat (udělám, uděláš…). The imperfective future needs the auxiliary budu plus the imperfective infinitive dělat.

See the imperfective future with budu.

Imperative

The -á- class drops the -á- and adds -ej for the singular informal command.

There is a meaningful aspect split here too: a plain positive command is usually perfective ("get it done"), while telling someone to keep at something, or a general/standing instruction, is imperfective.

Conditional

The conditional uses the l-participle plus the conditional auxiliary bych, bys, by…, again a second-position clitic.

Government: accusative object

dělat/udělat takes a direct object in the accusative (the thing being done or made). The recipient, if any, goes in the dative, exactly like dát.

Common mistakes