Стоит ли брать зонт, если дождь уже закончился?

Стоит ли is a very common way to ask whether something is worth doing or advisable.

In this sentence, Стоит ли брать зонт...? means something like:

• Is it worth taking an umbrella...?
• Should I take an umbrella...?

Literally, стоить means to cost, but in this pattern it does not mean money.
The structure стоит ли + infinitive means is it worth doing...?

Examples:

• Стоит ли ехать? — Is it worth going?
• Стоит ли покупать это? — Is it worth buying this?

Ли is a question particle used in yes/no-type questions, especially in more neutral or written-style Russian.

It usually comes after the word being questioned or focused. Here, the speaker is questioning whether it is worth it, so ли follows стоит:

• Стоит ли брать зонт?

You can think of it roughly as:

• Is it worth taking an umbrella?

English does this with word order (Is it... ?), but Russian often uses ли instead.

This is about verb aspect.

• брать = imperfective
• взять = perfective

In questions like Стоит ли брать...?, Russian often uses the imperfective because the speaker is asking about the general action or practical decision, not emphasizing a completed result.

So Стоит ли брать зонт? sounds natural as:

• Is it worth taking an umbrella?

You may also hear Стоит ли взять зонт?, and that is possible too. It can sound a bit more like:

• Should I take an umbrella this one time?

But брать is very common in this kind of general, everyday decision-making question.

It is in the accusative, but for many inanimate masculine nouns, the accusative singular looks exactly the same as the nominative singular.

So:

• nominative: зонт
• accusative: зонт

Because зонт is:

• masculine
• singular
• inanimate

the form does not change.

Compare:

• Я беру зонт. — I’m taking an umbrella.
• Я вижу стол. — I see a table.

But with animate masculine nouns, the accusative changes:

• Я вижу брата. — I see my brother.

Если means if.

It introduces the condition:

• если дождь уже закончился — if the rain has already stopped

So the whole sentence is:

• Is it worth taking an umbrella if the rain has already stopped?

This is a very straightforward use of если.

Because закончиться is the normal verb for to end / to come to an end when something ends by itself.

So:

• дождь закончился = the rain ended / the rain has stopped

Here the verb is закончиться, not закончить.

Compare:

• Я закончил работу. — I finished the work.
  Here закончил is transitive: someone finished something.
• Работа закончилась. — The work ended.
  Here закончилась means the work came to an end.

So дождь закончился is the natural way to say the rain stopped / ended.

The -ся is part of the verb закончиться.

Many Russian verbs with -ся describe something happening to the subject itself or happening without an external object. Here it means something like:

• the rain came to an end
• the rain ended

So:

• закончить = to finish something
• закончиться = to end

This is a very common verb pair in Russian.

Because the verb in the past tense agrees with the subject, and the subject is дождь.

• дождь is masculine singular
• so the past tense form is закончился

Compare:

• буря закончилась — the storm ended
  (буря is feminine)
• лето закончилось — summer ended
  (лето is neuter)

So the ending tells you the gender and number of the subject.

Уже means already.

It adds the idea that the rain has stopped by now or has stopped sooner than might matter for the decision.

So:

• если дождь закончился — if the rain stopped
• если дождь уже закончился — if the rain has already stopped

In this sentence, уже makes the question more natural, because the speaker is deciding whether an umbrella is still necessary.

They are very close in meaning, but not exactly identical in tone.

• дождь закончился = the rain ended
• дождь перестал идти = the rain stopped falling / stopped raining

Both are natural.
Дождь закончился is often a little more compact and direct.
Дождь перестал идти is slightly more descriptive.

In everyday speech, either could work here.

Yes.

Russian often leaves the subject unstated when it is understood from context or when the sentence is meant more generally.

So Стоит ли брать зонт...? can mean:

• Should I take an umbrella...?
• Should you take an umbrella...?
• Is it worth taking an umbrella...?
• even a more general Should one take an umbrella...?

In real conversation, the intended subject usually comes from the situation.

Yes, the word order is natural.

• Стоит ли брать зонт, если дождь уже закончился?

This is the most neutral and standard order.

Russian word order is flexible, so you could rearrange parts for emphasis, but this version sounds normal and idiomatic.

For example:

• Если дождь уже закончился, стоит ли брать зонт?

This is also correct. It just puts the condition first:

• If the rain has already stopped, is it worth taking an umbrella?

It is basically neutral.

Nothing in it is slangy or especially formal.
You could say it in everyday conversation, and you could also write it.

The structure стоит ли + infinitive is slightly more thoughtful or reflective than a blunt command-style question, but it is still very normal and common.