Last updated: March 2026
Understanding Your Menstrual Cycle
The menstrual cycle is a monthly process orchestrated by hormones that prepares the body for pregnancy. A typical cycle ranges from 21 to 35 days, measured from the first day of one period to the first day of the next.
Your cycle has four main phases. Menstruation (days 1-5) is when the uterine lining sheds. The follicular phase overlaps with menstruation as follicles in the ovary mature. Ovulation occurs when a mature egg is released, typically around 14 days before your next period. The luteal phase follows, where progesterone maintains the uterine lining until the cycle restarts.
Tracking your cycle reveals patterns invisible to memory alone. You might discover that headaches consistently arrive two days before your period, or that your energy peaks mid-cycle. This awareness helps you plan, prepare, and understand your body better.
Factors that can affect your cycle include stress, significant weight changes, travel, illness, excessive exercise, and hormonal conditions like PCOS or thyroid disorders. If your cycles are consistently outside the 21-35 day range, or if you experience sudden changes in pattern, consulting your healthcare provider is recommended.
Frequently Asked Questions
How do I track my menstrual cycle?
Tap dates on the calendar to mark each day of your period, starting with the first day of full bleeding. The tracker automatically detects your cycles and calculates your average cycle length, predicting future periods as you log more data.
Is my menstrual data private?
Yes, completely. All data is stored in your browser's localStorage on your device only. Nothing is sent to any server. There are no accounts, no cloud storage, and no third-party access to your health information.
What is a normal menstrual cycle?
A normal menstrual cycle ranges from 21 to 35 days, measured from the first day of one period to the first day of the next. The average is 28 days, but healthy cycles can vary. Periods typically last 2-7 days.
Why should I track my menstrual cycle?
Tracking helps you predict upcoming periods, identify patterns in symptoms, detect irregularities early, and provide your healthcare provider with accurate cycle data. It also helps you understand your body's natural rhythms.
How many cycles do I need to track for accurate predictions?
After logging 3 or more complete cycles, predictions become significantly more accurate. The tool averages your recent cycle lengths rather than using generic estimates, so more data means better predictions.