If your native language only has the basic “and” vs “but” distinction, Russian conjunctions а and но may be a bit confusing. How do you use them, and what’s the difference?

I will explain the difference on an intuitive level below and will include links to additional resources at the bottom.

Но: Contrasting the Entire Situation

If we have two situations/observations that contradict each other, we use но (but).

• Мы опозда́ли на полчаса́, но конце́рт ещё не начался (We were half and hour late, but the concert hadn’t started).

Based on our knowledge of the world, there is an inherent contradiction between the two observations. Here, the speaker expects the concert to have started because the speaker was half an hour late, but for some reason, that did not happen.

А: Contrasting Parallel Attributes Of Two Different Things

А is used to make a parallel comparison, so to speak. We have two different things (they don’t have to be the subject of the sentence, but more on that later), and we are contrasting some of their attributes. Here is a simple example:

• Моя́ ма́ма рабо́тает в ба́нке, а па́па — в шко́ле (My mother works in a bank, and my father works in a school).

Here, our subjects are mother and father. We are comparing where they work (“workplace attribute”), and their workplaces happen to be different. We do not use но in this situation because there is no inherent logical contradiction between one parent working at a bank and the other in a school.

If they both worked in the same place, this sentence could read:

• Моя́ ма́ма рабо́тает в ба́нке, и мой па́па рабо́тает в ба́нке (My mother works in a bank, and my father works in a bank).

A less repetitive way of saying that would be “И моя мама, и мой папа работают в банке” (Both my mom and dad work in a bank).

For cases where the “things” are not the subject of the sentence, they can, for example, contrast different activities done by the same person.

• Я живу́ на окра́ине, а рабо́таю в це́нтре (I live on the outskirts and work in the center).

Note that here a construction with но would also be possible.

• Я живу́ на окра́ине, но рабо́таю в це́нтре (I live on the outskirts but work in the center).

The difference is fairly subtle and depends on your perspective. A is used to add new information (“I told you where I lived, now let me tell you more about where I work, which happens to be a different place”), and но to highlight a contradiction (“Even though I live on the outskirts, and it’s inconvenient for me to commute, I still work in the center”).

А: Making Corrections

I’ve also seen a useful explanation that а is used to provide a correction for wrong information.

• Я учу́сь не в шко́ле, а в университе́те (I am not in [primary/secondary] school but in university).

The second location is a correction of the first one, so to speak. We infer that the first location was wrong.

Но: Reconciling Contradictory Attributes

As opposed to the situation above, we may have a sentence where the same thing (subject or not) has different attributes that may be surprising to have at the same time. Note that I use the word “attributes” loosely in this article, and this word does not refer exclusively to adjectives.

• Я мно́го рабо́таю, но ма́ло получа́ю (I work a lot but earn little).

Here we have a contradiction: we expect a person who works a lot to earn a lot, but that is not the case.

To complicate matters further, it is possible to reformulate the same observation with а.

• Я рабо́таю мно́го, а получа́ю ма́ло.

This construction is explained by the “parallel contrast” section above.

Additional Resources

• Quora answer about the difference between но and а
• RT Learn Russian explanation of и, а, and но
• StackExchange answer about а and и