The Conditional: би / б

The Ukrainian conditional — more precisely the умо́вний спо́сіб, the mood of "would" and hypotheticals — is the single easiest verb form in the language to build, because it has no conjugation of its own. You take the past tense of the verb and add one small, unchanging particle: би or б. That is the entire formula. Я чита́в би = "I would read." This page shows the formula, the gender that comes along for free (because the base is the past tense), where the floating particle can go, and how it fuses with conjunctions into якби́ ("if") and щоб ("so that"). The meanings and uses of the conditional are on conditional uses; this page is about the form.

The formula: past tense + би / б

There is one rule, and it is this:

Conditional = past-tense verb + the particle би (after a consonant) / б (after a vowel).

The past tense supplies all the inflection — person, number, and gender — and the particle би/б adds the "would" / hypothetical meaning. The particle itself never changes for person or anything else; only its shape (би vs б) varies, and that purely for sound.

би or б? The euphonic choice

Which form you use depends purely on the sound before it — it is a question of euphony, not grammar:

• б after a vowel: Я б сказа́в, Вона́ зроби́ла б, Хто б поду́мав (after the vowel-final я, -ла, хто).
• би after a consonant: Він би сказа́в, Хтось би прийшо́в, Прийшо́в би (after the consonant-final він, хтось, -в).

The principle is simply that Ukrainian avoids clusters of consonants and prefers an even alternation of vowels and consonants — so it slims the particle to б when a vowel precedes, and keeps the fuller би when a consonant precedes. In careful writing, follow the rule; in fast speech you will hear both, but matching the particle to the preceding sound is what reads as polished.

The conditional is gendered — because the past tense is

This is the consequence English speakers least expect. Since the conditional is built on the past tense, and the Ukrainian past tense marks gender in the singular, the conditional is gendered too. "I would do" is зроби́в би if "I" am male and зроби́ла б if "I" am female. There is no genderless "would do" — you must pick the form that matches the subject.

One form for "would do" AND "would have done"

Ukrainian does not split the conditional into present and past the way English ("would do" vs "would have done") or French does. There is one conditional form, and time is read from aspect and context. The same зроби́в би can mean "would do" (now/future) or "would have done" (in the past), and the surrounding words tell you which.

The particle floats: where би / б can sit

The particle би/б is a clitic — a small, unstressed word that leans on a neighbour — and it is mobile. It does not have to follow the verb; it gravitates toward the most prominent word in the clause, very often right after the first stressed word, or after a conjunction. All of these are correct, with slightly different emphasis:

The strong tendency is for the clitic to come early in the clause — typically right after the first stressed element — rather than be left dangling at the end. So Я б хоті́в feels at least as natural as Я хоті́в би, and learners should be comfortable producing both. The general placement rules for clitics are on clitics and particle placement.

The particle fuses with conjunctions: якби́ and щоб

When би/б meets certain conjunctions, the two fuse into one word. The two you must know:

• як + би → якби́ — "if" (for hypothetical / counterfactual conditions): Якби́ я знав… "If I knew / had known…"
• що + б → щоб — "so that / in order to / that" (for purpose and after verbs of wishing): Я хо́чу, щоб ти прийшо́в "I want you to come."

These are not optional spellings — якби́ and щоб are the standard single words. Inside a якби́-clause and a щоб-clause, the verb is still in the conditional/past base (which is exactly where the fused б came from): Якби́ я знав, Щоб ти знав.

The deeper behaviour of щоб-clauses (purpose, wishing, requesting) is on щоб-clauses; якби́ and the full counterfactual sentence are on conditional sentences.

Source-language comparison

For an English speaker, two things are new. First, there is no auxiliary "would" — Ukrainian does not bolt a helper onto a base verb; it adds a one-letter particle to the past tense. So "would read" is literally "read-(past) + б." Second, and more surprising, the conditional is gendered: because it rides on the past tense, "I would do" is зроби́в би from a man and зроби́ла б from a woman. English "would" is invariant, so you have to consciously track gender here that English never asks you to mark. The upside is huge, though: once you can form the past tense, you already know the conditional — just add б/би. There is no third paradigm to learn.

For a Russian speaker, this transfers almost one-for-one: Russian forms the conditional the same way (past tense + бы), and the gendering works identically (сде́лал бы / сде́лала бы → зроби́в би / зроби́ла б). The differences are surface: Ukrainian's particle is би/б (with the euphonic vowel/consonant rule) rather than бы, and the fusions are якби́ and щоб (where Russian has е́сли бы / что́бы). Note that Ukrainian applies the euphonic б-after-a-vowel rule more visibly in writing than Russian does. Otherwise the mechanism is the same.

Common Mistakes

Key Takeaways

• Conditional = past-tense verb + би/б. No special conjugation; the past supplies person, number, and gender.
• би after a consonant, б after a vowel — a purely euphonic choice (Він би / Я б).
• The conditional is gendered: зроби́в би (masc.), зроби́ла б (fem.), зроби́ли б (plural).
• One form covers "would do" and "would have done"; aspect and context supply the time.
• The particle floats — Я хоті́в би / Я б хоті́в / Хоті́в би я are all valid, with the clitic preferring an early slot.
• It fuses with conjunctions: як + би → якби́ ("if"), що + б → щоб ("so that"), each written as one word.