usually with a 28 day cycle you ovulate around day 12. So with a 30 - 32 day cycly you would probably ovualte around days 13-17. So best bet for getting pg.....have sex 3-4 days before you are supose to ovulate and 3- 4 days after. Look on you calander that you keep track of you cycles on and look at the next day you are suppose to start you period again and count back 17 day then start having sex 3- 4 days earlier than that then cont' to have sex every day for about 7-8 days. That's what I did for the first time after reading about it online and it worked! I had been trying for the past 4 years! And finally did it. I'll be 9 weeks tomorrow! Good luck.

I don't know why different calenders would tell you different length cycles. It should be easy enough to count. How are you tracking your cycles?

Ways to tell when you ovulate include taking your temp every morning and plotting it over your cycle and taking the tests in an ovulation predictor kit.