Мне всё равно, какой фильм мы посмотрим вечером.

Because мне is the dative case of я.

The expression мне всё равно is a set phrase that literally works like to me, it is all the same. Russian often uses the dative case for the person who experiences a feeling, attitude, or state.

So:

• я = I
• мне = to me

In this sentence, мне всё равно means I don’t care or it makes no difference to me.

You will see the same pattern in other expressions too:

• мне холодно = I am cold
• мне интересно = I am interested
• мне нравится = I like it

So grammatically, Russian is not saying I don’t care the way English does. It is saying something more like to me, it is all the same.

Here всё равно means it makes no difference, I don’t mind, or I don’t care.

Literally, it is close to all the same.

So:

• Мне всё равно = It’s all the same to me / I don’t care / I don’t mind

A useful thing to know is that всё равно can also mean anyway in other contexts, so learners sometimes get confused.

Compare:

• Мне всё равно, какой фильм мы посмотрим. = I don’t care which film we watch.
• Я всё равно пойду. = I’ll go anyway.

So in your sentence, всё равно is part of the expression мне всё равно and means I’m indifferent.

The comma separates the main clause from the subordinate clause.

The sentence has two parts:

• Мне всё равно = I don’t care
• какой фильм мы посмотрим вечером = which film we will watch tonight

In Russian, subordinate clauses are normally separated by a comma, even when English might not always emphasize it as strongly.

So the structure is:

• Мне всё равно, какой фильм мы посмотрим вечером.

You can think of it as:

• I don’t care, which film we watch tonight

Even though that English punctuation may feel unusual, in Russian the comma is standard and required here.

Here какой means which.

It agrees with фильм in gender, number, and case:

• какой = masculine singular
• фильм = masculine singular

So какой фильм means which film.

This can be confusing because какой can also mean what kind of in other contexts.

For example:

• Какой это фильм? = What kind of film is it?
• Какой фильм мы посмотрим? = Which film will we watch?

In your sentence, the meaning is clearly which film, because the speaker is talking about choosing one film from possible options.

In Russian, both какой and который can sometimes relate to which, but they are used differently.

In this sentence, какой фильм is the natural choice because it means which film / what film in the sense of selecting one option.

Который is more often used:

1. For which one when the set is more clearly defined
2. For ordinal meanings like first, second, third
3. In questions like What time is it?

Examples:

• Который фильм ты выбрал из этих трёх? = Which film did you choose out of these three?
• Который час? = What time is it?

In your sentence, какой фильм sounds natural and general: I don’t care which film we watch tonight.

Yes, it is functioning as the direct object, so it is in the accusative case. The reason it looks unchanged is that фильм is a masculine inanimate noun, and for masculine inanimate nouns, the accusative singular is the same as the nominative singular.

So:

• nominative: фильм
• accusative: фильм

That is why you do not see a different ending.

Compare with an animate masculine noun:

• Я вижу брата = I see my brother

Here брат changes to брата in the accusative because it is animate.

So in your sentence, фильм really is accusative in function, even though its form stays the same.

Посмотрим is the perfective future of посмотреть, and it fits very naturally here because the sentence refers to watching a film as a completed event in the future.

So:

• смотреть = imperfective, process / repeated action
• посмотреть = perfective, one completed viewing

Forms:

• мы смотрим = we are watching / we watch
• мы будем смотреть = we will be watching
• мы посмотрим = we will watch

In this sentence, Russian prefers посмотрим because the idea is which film we will end up watching.

Using будем смотреть is possible in some contexts, but it shifts the focus more toward the process:

• Мне всё равно, какой фильм мы будем смотреть вечером.

This is also understandable, but посмотрим is usually the more idiomatic choice when talking about choosing a film for the evening.

Because the action has not happened yet. The sentence is about a film that we will watch tonight.

The word вечером helps show that the action is in the future context of this evening / tonight, so Russian uses the future:

• мы посмотрим = we will watch

If the sentence were about the past, it would be:

• Мне было всё равно, какой фильм мы посмотрели вечером.

If it were about the present in a general sense, the structure would be different.

So the future tense is simply matching the meaning: the decision concerns a future viewing.

Вечером means in the evening or tonight, depending on context.

It is the instrumental case of вечер, but in expressions of time Russian often uses forms that must simply be learned as standard adverbial expressions.

So:

• утром = in the morning
• днём = in the daytime / during the day
• вечером = in the evening
• ночью = at night

In your sentence, вечером tells you when the watching will happen.

There is no form вечероми here. That is not a correct form for this word.

Yes. Russian word order is more flexible than English word order, although different orders can sound more natural depending on emphasis.

The neutral version is:

• Мне всё равно, какой фильм мы посмотрим вечером.

You could also say:

• Мне всё равно, какой фильм вечером мы посмотрим.
• Какой фильм мы посмотрим вечером, мне всё равно.

These are grammatically possible, but they place emphasis differently.

The original version sounds natural and neutral:

• first the speaker’s attitude: Мне всё равно
• then the content of that attitude: какой фильм мы посмотрим вечером

So learners should usually stick with the original order unless they have a reason to shift the emphasis.

Yes, I don’t care is a common translation, but the exact tone depends on context.

Мне всё равно can mean:

• I don’t care
• I don’t mind
• It makes no difference to me

Sometimes I don’t care in English can sound a bit harsh or rude, while мне всё равно can be neutral. In a sentence like this one, I don’t mind which film we watch tonight may sound more natural in English.

So the Russian phrase itself is not automatically rude; it depends on tone and situation.

Yes. A few common alternatives are:

• Мне не важно, какой фильм мы посмотрим вечером. = It’s not important to me which film we watch tonight.
• Мне без разницы, какой фильм мы посмотрим вечером. = It makes no difference to me which film we watch tonight.
• Не имеет значения, какой фильм мы посмотрим вечером. = It doesn’t matter which film we watch tonight.

The differences are mostly about style and tone:

• мне всё равно = very common, neutral
• мне не важно = slightly softer, often polite
• мне без разницы = informal, sometimes a bit blunt
• не имеет значения = more formal

So the original sentence is a very normal and useful everyday way to say it.