Up to the end of the year; before the end of this year.
年末までにこの書類を提出してください。
Please submit these documents by the end of the year.
今年の売上目標は年末までに達成したい。
We want to reach this year's sales target by the end of the year.
セールは年末まで続く予定です。
The sale is expected to continue until the end of the year.
年末まで働くつもりですか、それとも休むつもりですか？
Do you plan to work until the end of the year, or will you take time off?