Trebati ("to need / should / ought to") is the most syntactically slippery high-frequency verb in Croatian, because it leads a double life. In one construction it is a personal verb: Trebam odmor ("I need a rest") — you are the subject, the thing needed is the object. In another it is impersonal: Treba mi odmor ("I need a rest", literally "rest is needed to me") — now the thing needed is the subject and you sit in the dative. And in a third use it means "should / ought to" with an infinitive. English flattens all of this into "need" and "should", so the trap is real and constant. This page lays out all three faces, the agreement they force, and the live prescriptive debate around them.
Aspect
Trebati is imperfective and has no aspectual partner — needing and obligation are states, not events. The complement infinitive (in the "should" sense) chooses its own aspect by meaning.
Present tense
Regular a-class: stem treba- + -m, -š, -∅, -mo, -te, -ju.
| Person | Form | Meaning (personal) |
|---|---|---|
| ja | trebam | I need |
| ti | trebaš | you need |
| on/ona/ono | treba | he/she/it needs |
| mi | trebamo | we need |
| vi | trebate | you need |
| oni/one/ona | trebaju | they need |
Trebam tvoju pomoć oko selidbe.
I need your help with the move. — personal: 'ja' subject, 'pomoć' accusative object.
Trebamo još malo vremena za odluku.
We need a little more time to decide.
The l-participle
Regular for an -ati verb: stem treba- + the l-participle endings.
| Gender / number | Form |
|---|---|
| masculine singular | trebao |
| feminine singular | trebala |
| neuter singular | trebalo |
| masculine plural | trebali |
| feminine plural | trebale |
| neuter plural | trebala |
The masculine trebao shows the vocalised -l (treba- + -l → trebao). The impersonal "should have" past uses the neuter trebalo (see below).
Perfect tense (perfekt)
Clitic biti + l-participle. In the personal sense it means "needed"; in the impersonal "should" sense it means "should have".
| Person | Masculine subject | Feminine subject |
|---|---|---|
| ja | trebao sam | trebala sam |
| ti | trebao si | trebala si |
| on / ona | trebao je | trebala je |
| mi | trebali smo | trebale smo |
| vi | trebali ste | trebale ste |
| oni / one | trebali su | trebale su |
Trebala sam pauzu, pa sam uzela slobodan dan.
I needed a break, so I took a day off. — feminine speaker, personal sense.
Trebao si me nazvati, čekala sam cijelu večer.
You should have called me, I waited all evening. — 'should have', masculine subject.
Future I (futur prvi)
The infinitive trebati drops its final -i before the clitic: trebat ću.
| Person | Infinitive first | Clitic first |
|---|---|---|
| ja | trebat ću | … ću trebati |
| ti | trebat ćeš | … ćeš trebati |
| on/ona/ono | trebat će | … će trebati |
| mi | trebat ćemo | … ćemo trebati |
| vi | trebat ćete | … ćete trebati |
| oni/one/ona | trebat će | … će trebati |
Trebat će nam veći stol za blagdane.
We'll need a bigger table for the holidays. — impersonal future with dative 'nam'.
Imperative
Trebati has no everyday imperative — you do not command someone "need!". Advice that would use trebati is rephrased with the conditional (trebao bi…) or a direct imperative of the main verb.
Conditional I (kondicional prvi)
The conditional is the home of the polite "should / ought to". bih-clitics + l-participle, agreeing with the person being advised.
| Person | Form (masc.) |
|---|---|
| ja | trebao bih |
| ti | trebao bi |
| on/ona/ono | trebao/trebala/trebalo bi |
| mi | trebali bismo |
| vi | trebali biste |
| oni/one/ona | trebali bi |
Trebao bi se ispričati, pretjerao si.
You should apologise, you went too far. — masculine addressee.
Trebali bismo krenuti, inače ćemo zakasniti.
We ought to get going, otherwise we'll be late.
Other forms
As a need/modal verb, trebati has no productive passive participle. The present verbal adverb trebajući exists but is vanishingly rare.
The three faces of trebati
Face 1 — personal "need": trebati + accusative
You are the grammatical subject; the thing needed is a direct object in the accusative. The verb agrees with you.
Trebam nove cipele za vjenčanje.
I need new shoes for the wedding. — 'ja' subject (trebam), 'cipele' accusative.
Trebaš li nešto iz dućana?
Do you need anything from the shop?
Face 2 — impersonal "need": treba mi + nominative
Here the thing needed becomes the subject (nominative), the verb agrees with it, and the person who needs sits in the dative. This is structurally identical to sviđati se and boljeti — the experiencer inversion. The agreement trap lives here: treba mi knjiga (singular subject) but trebaju mi knjige (plural subject → plural verb).
Treba mi tvoj savjet.
I need your advice. — 'savjet' is the subject (singular), 'mi' is the dative experiencer.
Trebaju mi naočale za čitanje.
I need reading glasses. — plural subject 'naočale' → plural verb 'trebaju'.
Što ti treba? — Trebaju mi baterije i ljepilo.
What do you need? — I need batteries and glue. — note the verb switches to plural for the plural things.
For the dative experiencer pattern across verbs, see Dative with Verbs and Adjectives and the Experiencer Inversion.
Face 3 — "should / ought to": (impersonal) treba + infinitive
In its modal sense, trebati stays frozen in the neuter/3sg treba and takes an infinitive: Treba raditi ("One should work / Work is needed"). This impersonal "should" makes no statement about who — it is a general norm. The personal "should" (advice to a specific person) is the conditional trebao/trebala bih + infinitive from the section above.
Treba paziti na cesti, posebno noću.
One should be careful on the road, especially at night. — impersonal 'treba' + infinitive.
Ne treba se brinuti, sve je pod kontrolom.
There's no need to worry, everything's under control. — impersonal negative.
Trebalo je to riješiti odmah.
That should have been dealt with right away. — neuter 'trebalo' for the impersonal past 'should have'.
The prescriptive debate
There is a genuine norm question worth flagging. Traditional Croatian prescriptivists insist that in the "should" sense, trebati must stay impersonal — Trebalo bi to napraviti ("It should be done") — and frown on the personalised Trebao bih to napraviti ("I should do that"), treating the latter as a contact-induced calque. In practice, the personal "should" (trebam ići, trebao bih ići) is overwhelmingly common in everyday speech and increasingly accepted. Our recommendation: in the "need" sense both faces are fully standard (personal Trebam knjigu and impersonal Treba mi knjiga); in the "should" sense, prefer the impersonal trebalo bi in careful writing, but know that the personal trebao bih is normal and understood everywhere. See The Two Faces of trebati.
Trebalo bi više ulagati u obrazovanje.
More should be invested in education. — impersonal, preferred in formal register.
trebati vs morati
Both render "should / must", but trebati is the softer, more neutral "should / ought to", while morati is hard obligation ("must, have to"). For genuine necessity, reach for morati; for advice, trebati.
Trebao bi se odmoriti, a moraš popiti lijek.
You should rest, and you must take your medicine. — 'trebati' = advice, 'morati' = firm necessity.
See Obligation: morati, trebati, valja and morati.
Common Mistakes
❌ Treba mi nove cipele.
Agreement error — in the impersonal construction the verb agrees with the plural thing: 'Trebaju mi nove cipele'.
✅ Trebaju mi nove cipele.
I need new shoes. — plural subject → plural verb.
❌ Ja trebam mi pomoć.
Mixed constructions — choose one: personal 'Trebam pomoć' OR impersonal 'Treba mi pomoć', never both.
✅ Trebam pomoć. / Treba mi pomoć.
I need help. — two valid constructions.
❌ Treba meni odmor.
Clitic order — the dative clitic 'mi' goes in second position: 'Treba mi odmor' (stressed 'meni' only for contrast).
✅ Treba mi odmor.
I need a rest.
❌ Trebaš da ideš doktoru.
Substandard in the western norm — prefer the infinitive: 'Trebaš ići doktoru' / 'Trebao bi otići doktoru'.
✅ Trebao bi otići doktoru.
You should go to the doctor.
❌ Ona je trebao novi mobitel.
Agreement error — personal 'trebati' agrees with its subject: 'Ona je trebala…'.
✅ Ona je trebala novi mobitel.
She needed a new phone.
Key Takeaways
- Trebati is imperfective, regular a-class: trebam, trebaš, treba, trebamo, trebate, trebaju.
- Face 1 — personal "need": Trebam X (X = accusative object, verb agrees with you).
- Face 2 — impersonal "need": Treba mi X (X = nominative subject, you = dative; trebaju mi for plural things).
- Face 3 — "should": impersonal treba / trebalo bi
- infinitive; personal trebao/trebala bih
- infinitive (common in speech, debated in careful writing).
- infinitive; personal trebao/trebala bih
- Trebati = soft "should / need"; morati = hard "must". Past "should have" is the neuter trebalo (bi).
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Start learning Croatian→Related Topics
- The Two Faces of trebatiB1 — Personal 'need' vs impersonal 'should', and the agreement traps.
- Obligation: morati, trebati, valjaA2 — Expressing 'must', 'should', and 'need to'.
- Mistake: The Experiencer Inversion (sviđati se, trebati, boljeti)B1 — Why 'I like the song' becomes 'the song pleases to me' — the verbs where the thing is the grammatical subject and the person is a dative or accusative experiencer.
- Dative with Verbs and AdjectivesB1 — Verbs and adjectives that govern the dative.
- morati (must/have to)A2 — Obligation modal 'must'.
- da + present vs the InfinitiveB1 — When to use the infinitive and when to use a da + present clause after modal and volition verbs — the same-subject choice, the different-subject rule, and the register split.