Menstrual Cycle Calculator

Find out when your next period will come and plan ahead with this online menstrual cycle calculator

Menstrual Cycle Calculator
First day of your last period
Average duration of your period:
Average duration of your cycle:
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Menstrual-CycleWhether you are trying to get pregnant or you need to know your ovulation period, to avoid pregnancy or to help you get pregnant, getting to know your menstrual cycle is important. With this calculator you can work it out easily!

Calculate your next period

The menstrual cycle calculator is capable of calculating the dates of your next periods for up to a year. To find out about yours, input the following data about your previous periods:

  • Date that your last period started
  • Duration of the period (in days)
  • Average duration between periods (in days)

With this information, the calculator can tell you the following:

  • Start and end of your next periods
  • Ovulation period of each cycle (days where you are most fertile)
  • Days that ovulation will occur
  • Possible due date if you become pregnant during the ovulation period of that cycle

Does the menstrual cycle calculator work for irregular periods?

No, the menstrual cycle calculator only works for regular cycles, those that remain constant between periods and for duration of periods. If your period is irregular, the menstrual cycle calculator will not be accurate and you should search for an alternative way to control your menstruation.


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