To express that something must be done "by" a certain deadline, Russian uses the preposition к followed by the Dative case.
Days of the Week
Apply standard Dative case endings to days of the week:
- Masculine nouns ending in a consonant add -у (понедельник → к понедельнику).
- Feminine nouns ending in -а change to -е (среда → к среде).
| We must complete the launch by Wednesday. | Мы должны завершить запуск к среде. |
| They must finish the project by Monday. | Они должны закончить проект к понедельнику. |
If the following word starts with certain consonant clusters, like вторник (Tuesday), use ко instead of к for easier pronunciation (ко вторнику).
| The designers are finishing the final layouts by Tuesday. | Дизайнеры заканчивают финальные макеты ко вторнику. |
Times of Day and Exact Hours
General times of day also take Dative endings. Masculine words like обед (lunch) and вечер (evening) take -у. The word for noon (полдень) changes to к полудню.
| We need to finish the shipment by lunchtime. | Нам нужно закончить отгрузку к обеду. |
| You need to approve the final layout by evening. | Тебе надо согласовать финальный макет к вечеру. |
| The director is planning the launch and shipment by noon. | Директор планирует запуск и отгрузку к полудню. |
For a specific clock time, put both the number and the word for "hours" into the Dative case, such as к пяти часам (by five o'clock).
| Hand in the report by five o'clock. | Сдайте отчёт к пяти часам. |
Plural Deadlines
If your deadline is a plural noun like the weekend (выходные), use the Dative plural ending. Since выходные declines like an adjective, it becomes к выходным.
| I would like to approve the budget by the weekend. | Я хотел бы согласовать бюджет к выходным. |
You will frequently see these deadlines paired with project milestone verbs like завершить (to complete) or согласовать (to approve):
| The manager wants to complete the preparation by Monday. | Менеджер хочет завершить подготовку к понедельнику. |