Calculator
How it works and when to use it
The calculator adds your cycle length (from the first day of one period to the first day of the next) to your last period to estimate the next ones, and your period length to estimate when each ends.
A normal adult cycle is 24 to 38 days long with bleeding for up to 8 days, as classified by the International Federation of Gynecology and Obstetrics (FIGO).
Reference: FIGO AUB System 1: Munro MG et al. Int J Gynaecol Obstet 2018;143:393-408 (normal frequency 24-38 days, duration up to 8 days)
Frequently asked questions
How long is a normal cycle?
Between 24 and 38 days in adults, with bleeding for up to 8 days, and it can vary a little from month to month.
Why is my period late?
Pregnancy is the first thing to rule out, other causes include stress, weight change, thyroid disorders, polycystic ovaries and breastfeeding.
When should I see a doctor?
When your cycles are regularly shorter than 24 or longer than 38 days, bleeding lasts more than 8 days, or you bleed between periods or after menopause.
Tools you may also need
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- Ovulation and fertile days calculator Your expected ovulation day and fertile days for three cycles.
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- Calorie calculator Maintenance calories, the calories for your goal and the time to reach it.
- Ideal weight calculator The lowest and highest healthy weight for your height, and what to lose or gain.
- Body fat percentage calculator Body fat from a tape measure, and fat mass in kilograms.
Clinic software for this specialty
Try Clinicato for your clinic
These calculators are free here for everyone, and in Clinicato 49 medical tools work inside the patient's file with the "Medical tools" add-on: filled from the visit and the vital signs, with the result added to the visit's plan, next to appointments, prescriptions and invoices.