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Ovulation calculator

How to calculate fertile days?

If you would like to know when your fertile window is due, monitor your body thoroughly. In order to calculate it accurately, you should know your average cycle length and how long your last menstruation was.

How ovulation calculator works

Kalkulator owulacyjny obliczy, kiedy przypadną Twoje dni niepłodne, płodne oraz owulacja. Pamiętaj jednak o tym, że istnieje szereg czynników, które mogą powodować ich przesunięcie.


menstruation fertile days ovulation

Menstruation calendar Bella

is a free mobile application that will help you better control your cycle.

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When am I in a fertile window?

  • Increased body temperature – regular body temperature measurements will allow you to determine when you are actually close to ovulation. During ovulation, your body temperature raises to approximately 37°C.
  • Cervical mucus – during ovulation, it is considerably more abundant, while its consistency changes from a thin to thick discharge similar to egg white.
  • Abdominal pain – during ovulation, many women suffer from strong abdominal and lower abdominal pain within the ovary area.
  • Changes in the cervix – during fertile days, the cervix becomes soft and rises.

What causes fertile days to shift?

Remember that the ovulation calculator and observing your body do not guarantee precise calculation of your fertile window. There is a range of factors that may cause ovulation and fertile days to shift, such as:
– strong stress,
– illness in the first cycle phase and antibiotic use,
– heavy physical strain,
– diet and weight loss,
– climate change,
– sleep deprivation,
– general fatigue.

Period Calculator

It is worth being prepared for your period. In order to estimate when it is due, you need to consider your average cycle length as well as the date when your last menstruation started and how long it lasted.

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Your personal calendar for pregnancy and the first months after childbirth. It contains many tips and practical tools, supporting parents from the moment of conception.

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