Period Calculator
Predict your next 6 periods, track your menstrual cycle, and never be caught off guard again.
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About Your Menstrual Cycle
The average menstrual cycle is 28 days, but a normal cycle can range from 21 to 35 days. The period itself (menstruation) lasts 2–7 days on average. This calculator uses your last period date and average cycle length to predict the start and end dates of your next 6 periods.
Phases of the Menstrual Cycle
- Menstrual phase (Days 1–5): Uterine lining sheds. This is your period.
- Follicular phase (Days 1–13): Overlaps with menstruation. Estrogen rises, a follicle matures in the ovary.
- Ovulation (Day 14 of a 28-day cycle): A mature egg is released. Your fertile window spans 5 days before to 1 day after.
- Luteal phase (Days 15–28): Progesterone rises to prepare the uterus. PMS symptoms (cramps, bloating, mood changes) often occur here.
What Can Affect Your Cycle?
- Stress, illness, or sudden weight changes
- Travel and disrupted sleep patterns
- Hormonal birth control
- Polycystic ovary syndrome (PCOS)
- Thyroid disorders
- Perimenopause (typically begins in the mid-40s)
When to See a Doctor
See your gynaecologist if your cycle is consistently shorter than 21 days or longer than 35 days, if you miss 3 or more periods in a row, if your period lasts longer than 7 days, or if bleeding is unusually heavy (soaking a pad or tampon every hour for several hours).
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Log periods, get reminders, track symptoms, and see patterns over time. Private — doctors see nothing.
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