koristiti (se) (to use) | Croatian Grammar

Koristiti ("to use") is a high-frequency verb whose real lesson is government, not conjugation. It runs as a doublet: you can say koristiti nešto (+ accusative) "use something" — the common, modern pattern — or the more formal, traditional koristiti se nečim (+ instrumental) "make use of something". Both are correct standard Croatian; they differ in register and shade of meaning. On top of that, koristiti has an intransitive life meaning "to be of use / to benefit" (Koristi li to? "Is that any use?"). And like all -iti loan-flavoured verbs of this kind it is bi-aspectual — one form for both aspects. We will build the page around the accusative/instrumental doublet.

Aspect

Verb	Aspect	Present 1sg	Core sense
koristiti	bi-aspectual	koristim	use; make use of; be of use
koristiti se	bi-aspectual (reflexive)	koristim se	make use of something (+ instrumental)

Koristiti is bi-aspectual: the single form serves as both imperfective ("I use / I'm using") and perfective ("I (will) use [once]"), with context deciding. When a sharply perfective "use [up] / make use [on one occasion]" is needed, speakers reach for prefixed derivatives — iskoristiti ("use up, take advantage of, seize") most of all, also upotrijebiti as a near-synonym. The general behaviour of such verbs is on bi-aspectual and suppletive verbs.

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For a clean perfective "make full use of / seize", learn the partner iskoristiti: Iskoristila je priliku "She seized the opportunity", Iskoristi vikend "Make the most of the weekend". Plain koristiti stays neutral and bi-aspectual; iskoristiti adds the completed, "to the full" reading.

Present tense

Koristiti is a regular i-class verb (stem korist-, endings -im, -iš, -i, -imo, -ite, -e). The reflexive koristiti se adds the clitic se. The 3rd-person plural is the bare -e (koriste), not -iju.

Person	koristiti	koristiti se
ja	koristim	koristim se
ti	koristiš	koristiš se
on/ona/ono	koristi	koristi se
mi	koristimo	koristimo se
vi	koristite	koristite se
oni/one/ona	koriste	koriste se

Koristim ovu aplikaciju svaki dan za posao.

I use this app every day for work. — accusative pattern, the modern default.

U radu se koristim raznim izvorima.

In my work I make use of various sources. — instrumental pattern, more formal.

The l-participle

Regular for an -iti verb: stem koristi- + endings. Masculine koristio shows the vocalised -l.

Gender / number	koristiti
masculine singular	koristio
feminine singular	koristila
neuter singular	koristilo
masculine plural	koristili
feminine plural	koristile
neuter plural	koristila

Perfect tense (perfekt)

Clitic biti + l-participle. Because koristiti is bi-aspectual, koristio sam can read "I used / was using" or "I used [once]"; for an emphatically completed "I made full use of it" speakers often switch to iskoristio sam. The reflexive keeps se in the clitic cluster: koristio sam se.

Person	Masculine subject	Feminine subject
ja	koristio sam	koristila sam
ti	koristio si	koristila si
on / ona	koristio je	koristila je
mi	koristili smo	koristile smo
vi	koristili ste	koristile ste
oni / one	koristili su	koristile su

Godinama smo koristili isti recept za sarmu.

For years we used the same recipe for sarma. — accusative, habitual past.

Pri pisanju rada koristila se isključivo provjerenim izvorima.

In writing the paper she used only verified sources. — reflexive + instrumental, formal register.

Future I (futur prvi)

Koristiti → koristit ću (drops -i). Never write koristiti ću.

Person	koristiti	koristiti se
ja	koristit ću	koristit ću se
ti	koristit ćeš	koristit ćeš se
on/ona/ono	koristit će	koristit će se
mi	koristit ćemo	koristit ćemo se
vi	koristit ćete	koristit ćete se
oni/one/ona	koristit će	koristit će se

Za prezentaciju ću koristiti samo nekoliko slajdova.

For the presentation I'll use only a few slides.

Imperative

i-class imperatives end in -i, -imo, -ite.

Person	koristiti	koristiti se
ti	koristi	koristi se
mi	koristimo	koristimo se
vi	koristite	koristite se

Koristi sunčanu kremu, danas jako prži.

Use sunscreen, the sun's really strong today. — accusative imperative.

For "make the most of it / seize it" the perfective imperative Iskoristi! is the natural choice: Iskoristi priliku "Seize the chance".

Conditional I (kondicional prvi)

bih-clitics + l-participle.

Person	koristiti (masc.)
ja	koristio bih
ti	koristio bi
on/ona/ono	koristio/koristila/koristilo bi
mi	koristili bismo
vi	koristili biste
oni/one/ona	koristili bi

Ja bih koristio javni prijevoz da je bolji.

I'd use public transport if it were better.

Other forms

Passive participle: korišten, korištena, korišteno ("used"). Note the t → št alternation in the participle (korist- → korišt-). Used as an adjective — korišten auto "a used car", najčešće korišten alat "the most frequently used tool" — and in the passive: Ova metoda više se ne koristi / nije korištena "This method is no longer used / wasn't used".
Verbal adverb: koristeći (se) ("[by] using"): Riješio je problem koristeći novi alat "He solved the problem using the new tool".
Related words: korist (f.) "use, benefit, profit", koristan / korisna "useful", korisnik / korisnica "user", iskoristiti "use up / take advantage of", upotreba "use, usage".

Kupili smo korišten automobil, ali u odličnom stanju.

We bought a used car, but in excellent condition. — passive participle 'korišten' as adjective.

Key uses and government — the doublet

1. koristiti + accusative — "use something" (modern default)

The everyday pattern treats koristiti as a plain transitive verb: the thing used goes in the accusative. This is what you will hear most, especially in speech and contemporary writing. See the accusative direct object.

Koristiš li mobitel za plaćanje u trgovini?

Do you use your phone to pay in shops? — accusative 'mobitel'.

Ne koristim šećer u kavi.

I don't use sugar in my coffee. — accusative 'šećer'.

2. koristiti se + instrumental — "make use of" (formal/traditional)

The older, more formal construction adds the reflexive se and puts the thing in the instrumental: koristiti se nečim. Purists once preferred this as the "correct" pattern; today it reads as careful, formal, or written register. See the instrumental of means and the general verb government.

Putnici se mogu koristiti besplatnim WiFi-jem u vlaku.

Passengers may make use of free WiFi on the train. — formal, instrumental 'WiFi-jem'.

Koristim se rječnikom samo kad zapnem.

I use a dictionary only when I get stuck. — instrumental 'rječnikom', a careful register.

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Both halves of the doublet are standard. Rule of thumb: in speech and everyday writing, koristiti + accusative (koristim auto). In formal, official, or academic prose, koristiti se + instrumental (koristim se autom) sounds more polished. Pick one frame per clause — don't mix them.

3. Intransitive koristiti — "be of use / benefit"

With no object, koristiti means "to be useful, to do good". The person who benefits goes in the dative: koristiti nekomu "to benefit someone". See the dative with verbs and adjectives.

Koristi li to uopće? Meni se čini da samo gubimo vrijeme.

Is that any use at all? It seems to me we're just wasting time. — intransitive 'be of use'.

Svjež zrak i šetnja koriste svima.

Fresh air and a walk benefit everyone. — intransitive + dative 'svima'.

Common Mistakes

❌ Koristim se mobitel.

Mixed frames — either 'koristim mobitel' (accusative) or 'koristim se mobitelom' (instrumental, with 'se').

✅ Koristim mobitel.

I use my phone.

❌ Koristim rječnikom kad zapnem.

Without 'se', the object must be accusative: 'koristim rječnik'. The instrumental needs 'se': 'koristim se rječnikom'.

✅ Koristim se rječnikom kad zapnem.

I use a dictionary when I get stuck.

❌ Ova metoda se više ne koristiti.

A finite clause needs the conjugated form, not the infinitive: 'ne koristi'.

✅ Ova metoda se više ne koristi.

This method is no longer used.

❌ Kupili smo koristen auto.

Spelling — the participle has the t → št change: 'korišten', not '*koristen'.

✅ Kupili smo korišten auto.

We bought a used car.

❌ Koristiti ću novi alat.

The infinitive drops its -i before the clitic: 'koristit ću', never 'koristiti ću'.

✅ Koristit ću novi alat.

I'll use the new tool.

Key Takeaways

koristiti (koristim, koristio) is bi-aspectual; for a sharp completed "use up / seize" reach for iskoristiti.
The government doublet: koristiti nešto (+ accusative) — common, modern; koristiti se nečim (+ instrumental) — formal/traditional. Both standard; don't mix them in one clause.
Intransitive koristiti = "be of use / benefit", with the beneficiary in the dative: Koristi li to?, koristiti nekomu.
Passive participle / adjective korišten (t → št): korišten auto, više se ne koristi.
Future drops -i: koristit ću (never koristiti ću).

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