Period Calculator

About the Period Calculator

Tracking your menstrual cycle helps you anticipate your next period, plan around it, and monitor your cycle health. Regular, predictable cycles are a sign of reproductive health; significant irregularities can indicate hormonal imbalances worth discussing with a healthcare provider. Our period calculator predicts your next 12 periods based on your average cycle length and last period date.

How It Works

Next period date = Last period date + Average cycle length. A normal menstrual cycle ranges from 21 to 35 days, with 28 days being the textbook average. Menstruation typically lasts 2-7 days. Our calculator projects forward 12 cycles to give you a full-year view, accounting for your specific cycle length rather than assuming a 28-day cycle.

Tips & Best Practices

• ✓Normal period blood loss: 20-80 mL per cycle. Soaking more than one pad/tampon per hour suggests heavy bleeding.
• ✓Track start and end dates for 3 months to establish your personal cycle pattern.
• ✓Stress, illness, significant weight changes, and intense exercise can delay or skip periods.
• ✓Spotting between periods is common and often benign, but persistent spotting warrants medical evaluation.
• ✓Perimenopause (typically starts in the mid-40s) causes cycle lengthening and irregularity.

Who Uses This Calculator

Menstruating individuals planning travel, events, or activities around their cycle, athletes monitoring exercise-related menstrual changes, women tracking cycle regularity for health monitoring, and anyone using fertility awareness methods for either pregnancy planning or avoidance.