Same day (if arranged) to 4-6 weeks.
However the decision on whether you made to second round either later the same day or the following business day.
Notification usually happens right after, but as highlighted by some others here sometimes communication takes longer due to some mishaps in the handling of the decision from partners, to recruiting, to hr, to whom is in charge to call/write you. Those are extremely rare cases, in most cases you get notified the same day decision is made or the day after and if a date for second round is not set yet they will tell you to hold on for further communication.
hope this helps,