The menstrual cycle is usually divided into two phases. The point that divides them is ovulation.
The first phase is the follicular phase, which is the time frame that begins with the first day of your bleeding, and it continues until the day before you have your LH surge. The second phase is the luteal phase, which is the time in your cycle that begins with the LH surge and ends with menstruation.
The follicular phase of the cycle can vary from woman to woman and cycle to cycle. It usually ranges from 14-21 days. The luteal phase is usually constant from woman to woman and from cycle to cycle and is usually 14 days in length.
What is a Luteal Phase Defect?
Related Calculator: Calculate if your luteal phase is constant