koliko vs koji vs kakav (how much / which / what kind)

English asks about a noun with a small kit of question words — how much, how many, which, what, what kind, whose — and lets what and which slide into each other freely. Croatian draws the lines more sharply, and once you know where they fall the choice is mechanical. koliko asks about quantity ("how much / how many"). koji asks which one out of a known set ("which"). kakav asks about quality or type ("what kind of"). čiji asks whose. The pair learners most often confuse is koji versus kakav — "which car" versus "what kind of car" — so that contrast sits at the heart of this page.

The quick test

koliko — how much / how many (+ genitive)

Koliko asks about amount, and it answers to both English "how much" and "how many" — Croatian does not distinguish countable from uncountable here. It is invariable (it never changes its ending), and the noun it quantifies goes into the genitive: singular genitive for uncountables, plural genitive for countables. This genitive-after-quantity pattern is the same one used by numbers above four and by quantifiers like mnogo — see quantifiers.

A side note worth filing: koliko also serves as "how" before adjectives and adverbs — koliko star "how old", koliko daleko "how far" — staying invariable throughout. But its core job is the quantity question, and the genitive on the following noun is its fingerprint.

koji — which one (out of a set)

Koji picks one item out of a known, limited set. The defining feature is that the options already exist in the conversation: there are several cars in the lot, several days in the week, several books on the shelf, and you are asking the listener to select. Koji is an adjective: it declines and agrees with the noun in gender, number, and case.

The English cue is that koji answers a "which" where the set is bounded and known: which of these, which of those. Because koji declines fully, it is also the workhorse relative pronoun ("the man who…", "the book which…"), but in questions its job is selection from a set.

kakav — what kind of (quality / type)

Kakav asks about the quality, character, or type of something — not which specific one, but what sort. The expected answer is a description ("a fast one", "a red one", "a reliable one"), not a pick from a known set. Kakav also declines and agrees with its noun. The contrast with koji is the crux of the whole page:

Hold the pair in mind: Koji auto? expects the listener to point at one of the cars present; Kakav auto? expects a description of the sort of car wanted. English speakers slip here because "what car?" can mean either in casual English — Croatian forces you to decide whether you are selecting (koji) or describing (kakav).

čiji — whose

Čiji asks who the owner is. Like koji and kakav, it declines and agrees with the thing owned (not the owner). It is the question that the possessive answers — and the possessive system it probes (possessive adjective vs genitive vs svoj) is the subject of possessive adjective vs genitive.

For the full interrogative family alongside tko (who) and što (what), see interrogative tko and što, and for how these slot into question formation generally, wh-questions.

Why English speakers stumble here

The trouble is that English overloads two words. "What car do you want?" can mean either "which of these cars" (koji) or "what sort of car" (kakav) — English leaves it to context. And "how big?" uses the same "how" that "how many?" uses, even though Croatian splits these into koliko star versus koliko ljudi. So an English speaker arrives with one fuzzy slot where Croatian has four sharp ones, and the fix is to think about the answer you expect before you choose the word: a number (koliko), a pick from options (koji), a description (kakav), or an owner (čiji).

There is one more practical wrinkle. Because koji, kakav, and čiji are all adjectives, they must agree with the noun in gender, number, and case — and that case is set by the noun's role in the sentence, not by the question word. So "which book" can surface as koja knjiga (subject), koju knjigu (object), or koje knjige (genitive), all from the same koji. Koliko, being invariable, never changes — but it drags the counted noun into the genitive, which is its own kind of agreement to remember.

Common Mistakes

Key Takeaways

• koliko = how much / how many — invariable, and the counted noun goes into the genitive (Koliko ljudi?, Koliko vode?).
• koji = which one out of a known set — declines and agrees; expect the listener to select (Koji auto je tvoj?).
• kakav = what kind of — declines and agrees; expect a description / type (Kakav auto tražiš?).
• čiji = whose — declines and agrees with the thing owned (Čiji je ovo auto?).
• The central contrast: koji selects, kakav describes. English "what car?" hides this; Croatian makes you choose between picking one and describing the type.