When you urinate on a stick from an ovulation predictor kit, it will turn color the day before you ovulate, indicating a surge in luteinizing hormone (LH). This surge is what causes your ovary to release an egg. An ovulation kit increases your chances of conceiving by enabling you to time sex to within a day of the LH surge.
A basal body temperature (BBT) chart can tell you when you have already ovulated. Your basal body temperature and cervical mucus reflect your progesterone level, which is close to zero before you ovulate and rises dramatically after ovulation. When your progesterone level rises, so does your temperature, giving you a sign that you have ovulated.
A BBT chart tells you something about when you ovulated in a particular month, but it can't tell you exactly when to have sex (or uterine insemination) that same month. You have to chart your BBT for a few months and spot a pattern in your cycle before you can use it to predict when you're most fertile. An ovulation predictor kit, on the other hand, can give you advanced warning of ovulation the first month you use it. The main drawback to the kits is that they can be expensive, running between $15 and $50 per cycle.
And also, I hope this link could help you. I hope I could help you with this information. :-)