My last menstrual period was august 31, 2012when will be my next period?

Approx 28 days later: No way to know for sure. Most women cycle every 26-30 days but the best predictor of your next period is your own personal history of how often you've cycled in the past.

Right about now.: If you're reasonably regular it should be now. Do you use birth control? If so your pack should be empty. Have you had unprotected sex? If you miss this period, wait a week or two, then check a home pregnancy test.