Remember, your starting test day can change. It all depends on the length of your cycle. So start counting on day one of your period (the first day of bleeding or spotting) and stop counting on the first day of your next period. This is the length of your cycle.
So for example: I have a regular cycle of 28 days and started my period on the 15th of the month. Beginning with the15th as day one, I count forward 11 days and begin testing on the 25th.
Now a lot of people have very irregular periods, so when they ovulate can be different every month. Some say to use the average of the last three months, but I'll be honest, I don't agree. If my cycle is 26 days this time around, I'm going to start testing on the 9th day and test until I get a positive. It could get pricey I suppose, but I personally think it's worth it.
Hope this helps and good luck!!
at 1:02 AM on Feb. 27, 2009