Period Calculator

Track from the first day of one period to the first day of the next. Record start dates for several months to find your average. Most cycles are 21-35 days, with 28 being average. Apps or calendars help track patterns over time.

Irregular periods can result from stress, weight changes, excessive exercise, hormonal imbalances (like PCOS), thyroid issues, perimenopause, or starting/stopping birth control. Occasional irregularity is normal, but persistent changes warrant medical consultation.

Normal cycles range from 21-35 days. The average is 28 days, but only about 15% of women have exactly 28-day cycles. Variation of a few days between cycles is normal. Consistently short (<21) or long (>35) cycles should be discussed with a healthcare provider.

A typical period lasts 3-7 days, with the heaviest flow in the first 2-3 days. Periods shorter than 2 days or longer than 7 days may indicate hormonal imbalances. Heavy bleeding soaking through protection hourly needs medical attention.

The cycle has 4 phases: 1) Menstrual (days 1-5): bleeding occurs. 2) Follicular (days 1-13): egg develops. 3) Ovulation (day 14): egg released. 4) Luteal (days 15-28): body prepares for potential pregnancy or next period.