biti (to be) | Croatian Grammar

Biti is the single most important verb in Croatian. It is the copula ("X is Y"), the verb of existence ("there is"), and — in its clitic form — the auxiliary that builds the entire past tense (the perfekt). It is also deeply irregular: it has three present-tense series (full, clitic, negative) plus a separate perfective present (budem) that no other verb pairs with so visibly. This page lays out every form you need and shows where each one is actually used.

Aspect and partner

Biti is imperfective in its everyday sense ("to be"). Its perfective counterpart is budem- — historically a separate verb (budnuti / budem) that survives only as the perfective present of "to be." You meet budem in two places: after kad / ako clauses pointing to the future, and as the auxiliary of Future II (futur drugi). So when grammarians say biti "has no perfective partner," they mean it has no separate perfective infinitive — but functionally budem fills that slot.

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Think of biti as two verbs sharing one infinitive: the imperfective "is/was/will be" (forms jesam, bio, bit ću) and the perfective "be (at a future point)" (form budem). You will not confuse them in practice because they live in different sentences.

Present — the three series

The present tense has a full (stressed) series, a clitic (unstressed) series, and a fused negative series. Which you use depends on the job: full for questions, answers, emphasis, and clause-initial position; clitic for the everyday copula and the past auxiliary; negative for any negation.

Person	Full (stressed)	Clitic	Negative
ja	jesam	sam	nisam
ti	jesi	si	nisi
on / ona / ono	jest / je	je	nije
mi	jesmo	smo	nismo
vi	jeste	ste	niste
oni / one / ona	jesu	su	nisu

The clitic series cannot begin a clause — it leans on the first stressed word and sits in second position. The negative series is made of single fused words (ne + jesam → nisam); never write ne sam. The 3sg je is the same in the full and clitic columns; the bookish full alternative jest survives in contrastive writing (On jest dobar "He really is good").

Ja sam iz Hrvatske, a ona je iz Srbije.

I'm from Croatia, and she's from Serbia. — clitic copula 'sam' / 'je'.

Jesi li ti Marko?

Are you Marko? — full 'jesi' in a yes/no question with 'li'.

Nismo umorni, samo nam je dosadno.

We're not tired, we're just bored. — negative 'nismo' (clause-initial) and clitic 'je'.

Perfective present — budem

Budem is the perfective present of "to be." On its own it means "I'll be (at that point)"; it is required after future kad / ako, and it is the auxiliary of Future II.

Person	budem-present
ja	budem
ti	budeš
on / ona / ono	bude
mi	budemo
vi	budete
oni / one / ona	budu

Kad budem gotov, javit ću ti se.

When I'm done, I'll get in touch. — future 'kad' forces 'budem', not the present 'sam'.

Ako budeš slobodan, idemo na pivo.

If you're free, we'll go for a beer. — 'ako' + 'budeš' for a future condition.

The same budem series builds Future II with an l-participle (budem radio "if/when I have worked") — see Future II.

L-participle (the past form)

The l-participle agrees with the subject in gender and number. It is the building block of the perfect, the conditional, and the pluperfect.

Masc. sg.	Fem. sg.	Neut. sg.	Plural (m / f / n)
bio	bila	bilo	bili / bile / bila

Perfect (perfekt) — the everyday past

Perfect = clitic of biti + the l-participle. Because the auxiliary here is biti itself, the perfect of "to be" stacks two pieces of the same verb: bio sam "I was."

Person	Masculine subject	Feminine subject
ja	bio sam	bila sam
ti	bio si	bila si
on / ona	bio je	bila je
mi	bili smo	bile smo
vi	bili ste	bile ste
oni / one	bili su	bile su

Sinoć smo bili kod bake.

Last night we were at grandma's. — 'smo' + 'bili', the perfect of 'biti'.

Gdje si bila cijeli dan?

Where were you all day? — feminine 'bila' agreeing with a female addressee.

Future I (futur prvi)

Future I = clitic of htjeti + infinitive. The infinitive biti drops its final -i before the clitic: bit ću. In writing both bit ću and the merged biću exist, but standard Croatian prefers the split spelling bit ću.

Person	Future I
ja	bit ću
ti	bit ćeš
on / ona / ono	bit će
mi	bit ćemo
vi	bit ćete
oni / one / ona	bit će

Sutra ću biti u uredu cijeli dan.

Tomorrow I'll be in the office all day. — Future I 'ću biti'.

Imperative

The imperative is built on the budem- stem, not on jesam: budi (sg.), budimo (let's), budite (pl./polite).

ti	mi	vi
budi	budimo	budite

Budi miran, sve će biti u redu.

Be calm, everything will be fine. — imperative 'budi'.

Budite ljubazni i pričekajte trenutak.

Be kind and wait a moment. — polite/plural 'budite'.

Conditional I

Conditional I = the conditional auxiliary (bih, bi, bi, bismo, biste, bi) + l-participle. With "to be" this gives bio bih "I would be."

Na tvom mjestu bio bih oprezniji.

In your place I'd be more careful. — conditional 'bio bih'.

Participles and verbal adverbs

Biti has no passive participle (it is intransitive — there is nothing to be "be-en"). Its present verbal adverb is budući ("being"), which survives mainly in the fixed connective budući da ("since, because") and in buduć(i) da style writing. There is no productive past verbal adverb in everyday use.

Budući da je kasno, idemo kući.

Since it's late, we're going home. — the fossilised verbal adverb 'budući' in 'budući da'.

Key uses and government

Copula — links a subject to a nominative predicate (noun or adjective). The predicate adjective agrees in gender/number: On je umoran / Ona je umorna.
Existential / "there is" — Ima is the usual "there is" with a genitive, but biti covers location and presence: Nikoga nema vs Svi su tu.
Location — biti
- a place phrase: Knjiga je na stolu.
Auxiliary — clitic biti builds the perfect, the pluperfect, and (as conditional bih) the conditional.

On je dobar učitelj.

He's a good teacher. — copula + nominative predicate 'dobar učitelj'.

Ana je liječnica.

Ana is a doctor. — predicate noun in the nominative, no article needed.

Ključevi su na stolu u kuhinji.

The keys are on the table in the kitchen. — 'su' for location.

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Croatian has no zero copula. English drops "is" in headlines and some dialects ("She tired"), and many learner languages omit it in the present — but Croatian never does. Je (or another form of biti) is obligatory: Ona je umorna, never *Ona umorna.

Common Mistakes

❌ Ona umorna danas.

Incorrect — the copula 'je' is obligatory; Croatian has no zero copula.

✅ Ona je umorna danas.

She's tired today.

❌ Kad sam gotov, javit ću ti se.

Incorrect — a future 'kad' clause needs the perfective present 'budem', not 'sam'.

✅ Kad budem gotov, javit ću ti se.

When I'm done, I'll get in touch.

❌ Ne sam bio kod kuće.

Incorrect — 'ne' + 'sam' must fuse to 'nisam'.

✅ Nisam bio kod kuće.

I wasn't home.

❌ Sam student.

Incorrect — the clitic 'sam' cannot open a clause; it needs a host word.

✅ Ja sam student.

I'm a student. — 'sam' leans on 'Ja' in second position.

Key Takeaways

Biti has three present series — full jesam, clitic sam, negative nisam — plus the perfective present budem for future kad/ako clauses and Future II.
The l-participle bio / bila / bilo / bili builds the perfect (bio sam), the conditional (bio bih), and the pluperfect.
The imperative is budi / budimo / budite, built on the budem- stem.
The copula is never omitted: Ona je umorna, not Ona umorna.

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