Is my cycle regular?
Enter the dates when your last periods started: at least 3, ideally 4–6. The calculator will work out your cycle length and variation and tell you when to expect the next one.
Dates are stored only in this browser and are not sent anywhere.
Normal ranges follow the FIGO classification: a cycle of 24 to 38 days, a difference of up to 7–9 days between your shortest and longest cycle, and a period of no more than 8 days. This is not a diagnosis. If your periods are very painful or heavy, or you bleed between periods or after sex, see a doctor even if your cycle is regular.
What is a normal menstrual cycle?
According to FIGO, 24 to 38 days. The difference between your shortest and longest cycle is up to 7–9 days, and a period lasts no longer than 8 days.
How do I count my cycle length?
From the first day of one period to the first day of the next. Day one is the first day of real bleeding, not light spotting the day before.
What if my cycle is irregular?
There are many possible causes: stress, weight changes, the thyroid, prolactin, polycystic ovary syndrome. A consultation and a few tests chosen by your doctor will help find out.
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