How the phase labels fit together
A cycle is counted from the first day of one period to the first day of the next. Menstruation describes uterine bleeding, while follicular phase, ovulation, and luteal phase describe ovarian events. Menstruation and the early follicular phase therefore happen at the same time rather than one after the other.
In a simplified ovulatory cycle, hormone patterns usually progress in this order, but their timing and expression vary. Anovulatory cycles, hormonal contraception, life stage, and health conditions can change the pattern.
Menstruation: day 1 is the calendar anchor
Day 1 is the first day of menstrual bleeding. It is an event that is usually easier to record as a calendar date than internal hormone changes, which is why period trackers use it as an anchor.
MiniCycle measures cycle length from one recorded start date to the next. Other observations, such as cervical-mucus or temperature changes, can also be noticed, but MiniCycle does not use them to confirm a phase.
Cycle-length variation often comes before ovulation
The follicular phase runs from day 1 until ovulation. Follicles develop under hormonal signaling, and the uterine lining begins to rebuild. Its length can vary between people and between cycles.
Much cycle-length variation is associated with the timing before ovulation, while the luteal phase is often more stable. That does not let a calendar identify why one cycle changed; stress, illness, medications, energy availability, and other factors may be relevant and require individual assessment.
Ovulation is an event, not a measured app date
Ovulation is the release of an egg from an ovary. Because sperm can survive for several days and an egg has a much shorter life after release, pregnancy can result from intercourse before the event as well as around it.
MiniCycle marks one estimated ovulation date and highlights the 5 days before it through the day after it. That seven-date band is a generous calendar cue, not confirmation that ovulation occurred on the marked day.
The luteal phase is not fixed at 14 days
After ovulation, the follicle becomes the corpus luteum and produces progesterone. If pregnancy does not begin, hormone levels fall and menstruation follows. Research shows that the interval from ovulation to the next period is not identical in every person or cycle.
MiniCycle does not measure an individual's luteal phase. Its prediction engine applies an internal 9–14 day value based on cycle length and counts backward from the expected period. That rule creates a calendar estimate; it is not a clinical measurement.
How MiniCycle maps the phases onto a calendar
The app never measures hormones. It works from saved period start dates, using up to your latest 12 records. Once there are at least 10 measured intervals, it drops one shortest and one longest interval and takes the median. With little history, it starts from a 29-day default. The next period, the ovulation estimate, and the fertile window all hang off that one number.
Everything the calendar shows about phases is an inference from dates. That is why the dates are reference information for planning, not medical advice, contraception, or diagnosis. A phase estimate cannot tell you whether ovulation actually happened in a given month.
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