must / have to (obligation)
The core use: trebuie să + subjunctive. Who must do it is shown by the second verb.
Trebuie să plec.
I have to go.
Trebuie să știi asta.
You have to know this.
#30 · Verb
trebui
In Romanian, trebui means “must / have to (obligation)”. It’s the #30 most frequently used Romanian word. Below you’ll find how to use it, its forms, real example sentences, and common word pairings.
Meaning & Use
Romanian's "must", and the 30th most frequent word — but it does not conjugate for person. One form does every job: trebuie să plec, trebuie să pleci, trebuie să plece. The person is carried by the second verb after să, never by trebuie itself. Learn the four shapes trebuie / trebuia / ar trebui / a trebuit and you have the whole verb.
neutralmust (logical deduction)
The same form draws a conclusion: "it must be that…". Often trebuie să fie.
Trebuie să fie acasă.
He must be home.
Trebuia să fie o glumă.
It must have been a joke.
to need (something)
With a noun instead of a clause, and the person in the dative: îmi trebuie = "I need". Here alone a plural subject can pull the rare plural trebuie/trebuiesc.
Îmi trebuie ajutor.
I need help.
Ce-ți trebuie?
What do you need?
should / ought to (ar trebui)
The conditional softens obligation into advice — the polite way to tell someone what to do.
Ar trebui să dormi.
You should sleep.
N-ar trebui să fumezi.
You shouldn't smoke.
Forms you’ll actually hear
Ranked by how often each form shows up in spoken Romanian. The top 2 forms cover about 88% of everyday use — learn these first.
trebuie65%
trebui23%
Show 6 more forms
trebuia6%
trebuit5%
trebuiască<1%
trebuiau<1%
trebuiesc<1%
trebuind<1%
Conjugation
- Infinitive
- a trebui
- Past Participle
- trebuit
- Gerund
- trebuind
- Auxiliary
- a avea
- Reflexive
- No
- Transitivity
- intransitive
| Tense | eu | tu | el/ea | noi | voi | ei/ele |
|---|---|---|---|---|---|---|
| Present | trebuie | trebuie | trebuie | trebuie | trebuie | trebuie |
| Imperfect | trebuia | trebuia | trebuia | trebuia | trebuia | trebuia |
| Perfect compus | a trebuit | a trebuit | a trebuit | a trebuit | a trebuit | a trebuit |
| Future | va trebui | va trebui | va trebui | va trebui | va trebui | va trebui |
| Conditional | ar trebui | ar trebui | ar trebui | ar trebui | ar trebui | ar trebui |
| Subjunctive | să trebuiască | să trebuiască | să trebuiască | să trebuiască | să trebuiască | să trebuiască |
- The table is flat on purpose: a trebui is impersonal, so every column of a tense holds the same form. The person lives in the verb after să.
- No imperative and no gerund in normal use — you cannot command someone to have to.
- trebuie să + subjunctive is the everyday frame; trebuie a + infinitive is archaic.
- The second most frequent measured form, trebui, is not a present tense — it is the infinitive inside va trebui and ar trebui.
Examples
Trebuie să merg la muncă.
I have to go to work.
trebuie - trebuie never changes; merg is what says "I". Swap it for mergi and the sentence becomes "you have to go".
Ar trebui să vorbim.
We should talk.
ar trebui - Conditional ar trebui = "should". It is fixed too — never *aș trebui, even with eu.
Trebuia să-mi spui!
You should have told me!
trebuia - The imperfect trebuia + subjunctive is how Romanian says "should have" — a reproach about the past.
A trebuit să aștept două ore.
I had to wait two hours.
a trebuit - Compound past, always 3rd singular a trebuit, whoever the person is.
Îmi trebuie o pauză.
I need a break.
îmi trebuie - The "need" pattern: dative pronoun for the person, the thing needed as subject.
Nu trebuie să vii dacă nu vrei.
You don't have to come if you don't want to.
nu trebuie - Negated, it usually means "no need to" — for a prohibition Romanians prefer nu ai voie ("you're not allowed").
Do not conjugate this verb. *Trebui să plec, *trebuiesc să plec and *aș trebui are all wrong: the standard forms are trebuie (present), trebuia (imperfect), a trebuit (past), va trebui (future) and ar trebui (conditional), each unchanged for all six persons. The rare plural trebuiesc exists only in the "are needed" sense (Îmi trebuiesc bani) and even there trebuie is more common.
In expressions
Common phrases built around trebui — worth learning as whole units.
trebuie să— must, have to
lit. “it-must that”
ar trebui să— should, ought to
lit. “it-would-need that”