через vs за

cherez vs za — in/from now vs within/in the time it takes

What it really means

When talking about time, "через" means after an amount of time has passed from now or from a reference point: через час (in an hour), через неделю (in a week). "За" means within a period, in the time needed to complete something, or during the span in which a result is achieved: сделать за час (do it in an hour), выучить за неделю (learn it in a week).

Через points to when something will happen. За measures how long it takes to finish something. The time phrase after через or за is normally accusative: через час, за неделю.

Examples in natural speech

Я позвоню через час.
I will call in an hour.
Поезд отправится через десять минут.
The train will leave in ten minutes.
Я сделал это за час.
I did it in an hour.
Она выучила стихотворение за неделю.
She learned the poem in a week.
Мы встретимся через месяц.
We will meet in a month.
Он прочитал книгу за два дня.
He read the book in two days.

Common mistakes

Do not confuse the future point with the completion duration. Через час means the event starts or happens one hour from now; за час means the task takes one hour to complete. "Я закончу через час" means I will finish in an hour, while "Я закончил за час" means I finished within an hour.

Memory tip

Через points forward to a future moment; за measures the time needed to reach a result.

Frequently asked questions

What is the difference between через and за with time?

Через means after a period from now: через час (in an hour). За means within the time needed to complete something: сделать за час (do it in an hour).

How do you say in an hour in Russian?

Use "через час" when you mean one hour from now: "Я позвоню через час" (I will call in an hour). Use "за час" when something takes one hour to finish.

What does сделать за час mean?

Сделать за час means to complete something within one hour or in the time of one hour. It describes duration to a result, not when the action will begin.

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