The cycle in brief
A menstrual cycle is counted from the first day of one period to the first day of the next. The average is about 28 days, but anywhere from 21 to 35 days is normal. It runs in four phases driven by shifting hormones.
The four phases
1. Menstrual phase (days ~1–5)
Your period. The uterine lining sheds, hormone levels are low, and energy is often lower. Rest and gentle movement can feel good.
2. Follicular phase (days ~1–13)
Overlapping with your period and continuing after, oestrogen rises as the body prepares to release an egg. Many people feel more energetic, focused, and upbeat as this phase progresses.
3. Ovulation (around day ~14)
An egg is released — usually about 14 days before your next period. This is the most fertile time. Some notice a small temperature rise or changes in cervical mucus. Our ovulation calculator estimates this window.
4. Luteal phase (days ~15–28)
Progesterone rises. If pregnancy doesn't occur, hormones fall toward the end, which can bring PMS symptoms — mood changes, bloating, fatigue, cravings — before the next period begins.
Why tracking helps
Tracking your cycle reveals your personal patterns — average length, symptoms, energy shifts — so nothing catches you off guard. It helps you plan, spot irregularities early, and understand your body. Use our period calculator to predict upcoming dates.
What's normal — and when to check in
Some month-to-month variation is normal. See a healthcare professional if your cycles are very irregular, suddenly change, are extremely heavy or painful, or stop unexpectedly — and bring your tracked data, it's genuinely useful information.