Use this period calculator to track your menstrual cycle and predict your next period, ovulation date, and fertile window. Get accurate insights into your reproductive health.
The menstrual cycle is the monthly process that occurs in people with female reproductive systems. It typically lasts 28 days, though it can range from 21 to 35 days. The cycle has four main phases: menstruation, follicular phase, ovulation, and luteal phase. Understanding your cycle helps with fertility planning, understanding symptoms, and overall health management.
Each phase of the menstrual cycle is characterized by different hormonal and physical changes:
The fertile window is the period during which pregnancy is possible. It includes the 5 days before ovulation and the day of ovulation (6 days total). Sperm can survive up to 5 days in the reproductive tract, so intercourse during these days can result in pregnancy. The day before ovulation and the day of ovulation are the most fertile days.
Ovulation is when the ovary releases a mature egg. This typically occurs around day 14 of a 28-day cycle, but timing varies based on cycle length. During ovulation, some people experience ovulation pain (mittelschmerz), slight temperature rise, or changes in cervical mucus. The egg survives for about 12-24 hours if not fertilized.
While cycles typically range from 21-35 days, some variation is normal. However, you should consult a healthcare provider if:
Regular cycle tracking helps you understand your patterns, predict future periods, and recognize changes. Keep track of:
Understanding typical cycle patterns helps you identify what's normal for you:
While our period calculator provides helpful predictions, keep in mind:
The period calculator is a helpful tool for tracking patterns and making predictions, but accuracy depends on cycle regularity. If your cycles are consistent, predictions are typically within 1-2 days. For irregular cycles, tracking several months helps establish a more accurate average. Always consult a healthcare provider for specific health concerns.
Yes, but predictions will be less accurate. Track your cycle for 2-3 months to calculate an average cycle length, then enter that average into the calculator. If your cycle remains highly irregular, consult a healthcare provider to rule out underlying conditions.
The most fertile days are the 2-3 days before ovulation and the day of ovulation. For a 28-day cycle, this is typically days 12-16. Our calculator shows your fertile window. However, for fertility concerns, consult a healthcare provider for personalized advice.
Pregnancy tests are most accurate starting around the first day of a missed period. Testing too early may give false negatives. If you miss your predicted period and are concerned about pregnancy, consult a healthcare provider.
Common causes include stress, hormonal imbalances, polycystic ovary syndrome (PCOS), thyroid disorders, birth control changes, extreme exercise, significant weight changes, and illness. If your periods become irregular, consult a healthcare provider.
Yes, cycle length can change due to stress, illness, hormonal changes, medications, or lifestyle factors. It's normal for cycles to vary slightly (2-3 days), but significant changes warrant a healthcare provider consultation.
Premenstrual syndrome (PMS) is a group of symptoms occurring 5-11 days before your period. Common symptoms include mood changes, bloating, breast tenderness, fatigue, and food cravings. Symptoms typically improve once menstruation begins.