Daysy does not equate contraception! We help you to determine exactly WHEN you have to use contraception.

Calculating ovulation days made easy


The ovulation date calculator Daysy is quick, simple and 99.4% accurate!

Do you want to calculate the ovulation days in your menstrual cycle but dread the workload? We understand that, and it‘s why we developed Daysy! Daysy is a particularly convenient and easy to use ovulation date calculator that determines your fertile and infertile phases based on your basal temperature. Several decades of research and studies have gone into the development of its unique algorithm. With Daysy, knowing whether you are currently fertile is a matter of minutes in your morning routine. 

And this is how it works: Every morning before you get up, you remove the protective cap, activate Daysy via the push of a button and then place Daysy's highly sensitive test prod underneath your tongue. After 30 to 60 seconds, a beeping noise lets you know that the measurement was a success and Daysy immediately displays your current fertility status to you. If the red light is on, it means that you are fertile within the next 24 hours. If the green light is on, it means that for the next 24 hours, you will not be fertile. Calculating your fertile days based on your menstrual cycle really is that simple when you have Daysy!

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Calculate ovulation days with the menstrual cycle

So how does the calculation based on basal temperature work? The basis for Daysy to be able to calculate your fertile days based on your menstrual cycle is the natural female cycle and the influence that hormones have on your basal temperature. In the course of the cycle, the basal temperature changes in a certain way for every woman. Even when the strength of the temperature changes and the precise timing vary among every individual, this applies to all women and all menstrual cycles: Around the time of ovulation, the basal temperature rises by 0.3 to 0.5 degrees Celsius (32.5 – 41 degrees Fahrenheit) and stays slightly elevated until the onset of menstruation. Precisely this change in your basal temperature is what the ovulation date calculator Daysy can measure and evaluate with the help of its algorithm. Through this evaluation, Daysy can not only determine your ovulation days, but also the beginning and end of your fertile phases.


You can decide - with knowing your ovulation days

Daysy gives you the ability to choose what you want to do with your knowledge about your fertility. If you are, for instance, planning a pregnancy, Daysy can help you to find the perfect time to have sex. You are only fertile and able to conceive a child on the day of your ovulation, as well as a maximum of five days prior to that. This is what makes the right timing very important when you want to have a baby. With the right knowledge about your menstrual cycle and your ovulation date, you can help along your dream of becoming a mother.

If, however, you do not want to become pregnant, Daysy can show you when you have to use birth control. In general, it is safest to avoid sex on days that are displayed as red and are thus fertile days. If you want to have sex, you should use a barrier method such as a condom or a diaphragm. The correct use is important for the safety of these birth control methods and should ideally be trained beforehand during infertile days. 

Whether you are trying to get pregnant or trying to avoid it, Daysy and the free app DaysyView offer you the option to get to know your body and your menstrual cycle - 100 % natural, hormone-free and without any side effects.

Discover all the advantages of Daysy now and calculate your ovulation date based on your menstrual cycle!

USD 330.00

Daysy is a fertility tracker that uses the fertility awareness method by learning and tracking your menstrual cycle.

Daysy is a fertility tracker that uses the fertility awareness method by learning and tracking your menstrual cycle.

  • Fertility tracker Daysy (incl. battery)
  • Connection cable for your smartphone
  • Instructions for use