Irregular Period Calculator — Track & Predict Irregular Cycles
Calculate period predictions even with irregular cycles using your last cycle data.
Frequently Asked Questions — Menstrual Cycle Calculator
What makes a menstrual cycle irregular?+
A cycle is irregular if it varies by more than 7-9 days from month to month, is shorter than 21 days, or longer than 38 days. Common causes: PCOS (most common), thyroid disorders (hypo or hyper), elevated prolactin, extreme stress, overexercise, low body fat (<17%), eating disorders.
How do I track an irregular period?+
Track 3-6 cycles by recording the first day of each period. Calculate the average: add all cycle lengths and divide by the number of cycles. Use this average in a calculator for future predictions. A period tracking app makes this easier with visual charts.
When should I see a doctor about irregular periods?+
See a doctor if: cycles are consistently less than 21 days or over 38 days, you miss 3+ periods without pregnancy, you have sudden changes after years of regularity, periods last more than 7 days, or you experience severe pain (dysmenorrhea). PCOS, thyroid issues, and endometriosis are all treatable.