Use the calculator to work out when to expect your next menstrual bleeding. All you need to do is enter the date when your last menstrual bleeding began, and the calculator will tell you when to expect your next period.

Menstruation Calculator

Menstruation occurs in cycles. The ovaries prepare an egg (oocyte) for release and the womb (uterus) prepares a lining to nourish the egg if it is fertilised. When the egg is not fertilised, the lining of the womb is shed and a woman gets her period (menstrual bleeding).

Menstruation typically occurs in 28 day cycles so most women get their period every 28 days. However, some women have longer cycles and may only get their period every 40 days, while other have shorter menstrual cycles and may get their periods as often as every 21 days.

The menstruation calculator determines when your next period is due based on a 28 day menstrual cycle. All you need to do is enter the date when your last menstrual bleeding began, and the calculator will tell you when to expect your next period.

1. Select your menstrual cycle length: days
2. Select your last Menstrual Date:
Next Menstrual Date Due:

The information presented here is for general purposes only and should not be used to make diagnosis or treatment decisions. For specific information about your health you should see a health professional.

Reference
  1. Marieb EN, Hoehn KN. Anatomy and Physiology (3rd edition). San Francisco: Pearson Benjamin Cummings; 2008. [Book]

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More information

Menstruation For more information, see Menstruation.