14 days after ovulation is the rule of thumb, or around the time when you expect your period. some HPT's claim that they can detect the pregnancy hormone as early as five days before your period is expected
at 1:55 AM on Aug. 4, 2009
Many tests say ten days past ovulation.
Me, I preferred to wait until 18 days. I was charting and I knew form the chart before I even tested that it would be positive.