The carat (ct) is a unit of mass equal to 200 mg (0.2 g; 0.007055 oz) and is used for measuring gemstones and pearls. The current definition, sometimes known as the metric carat, was adopted in 1907 at the Fourth General Conference on Weights and Measures, and soon afterwards in many countries around the world.
Depending on your cycle length the most fertile days in the cycle varies: If you have 28 days between periods ovulation typically happens on day 14, and the most fertile days are days 12, 13, and 14. If you have longer cycles, say 35 days between periods, ovulation happens on day 21 and the most fertile days are days 19, 20, and 21.
You are fertile days 10-17 (counting the first day of your period as day #1) with days 13 and 14 being the most likely days you will conceive. Observe the consistency of your vaginal discharge as well. When it is mucous like (I know this sounds gross) as opposed to creamy or thin, you are in the ovulation phase.