Meet Daysy – your personal fertility tracker.

Daysy lets you make the choice!

Daysy is a fertility tracker that uses the fertility awareness method by learning and tracking your menstrual cycle. Daysy tells you when you are in your fertile window and when not. During your fertile window you can choose to plan a pregnancy, use a barrier method to prevent a pregnancy or postpose PIV (penis-in-vagina) sex to avoid pregnancy. It's your choice

Daysy calculates your fertile window and displays your fertility status as either red (you are fertile) or green (you are not fertile) light.

Daysy is not a contraception. Daysy tells you when you are in your fertile window. During your fertile window you can choose to use a contraceptive, i.e. a barrier method like a condom.

A fertility tracker as easy as 1,2,3...

Just 30 seconds once a day

  1. Every morning, take your temperature under your tongue.
  2. Confirm menstruation on the days you have it.
  3. Daysy evaluates your data and calculates your fertility status for the next 24 hours.

"I would absolutely recommend it. I love daysy and how easy it is to use, plus the tracking makes it simple to show my doctor how things are going. My husband and I are both very concerned about the effects of hormonal birth control, but don't want to throw caution to the wind. Daysy makes it easy for us to monitor fertility together, without all the side effects of HBC."

Lauren Halcik, HR Director

"I recommend Daysy to everyone. She and I are good friends. Switching to using Daysy instead of the pill or other hormonal birth control was the best decision I ever made. It helped eliminate the need for not only the pill, but it also helped reduce the postpartum depression I was suffering from, and allowed me to ween off my medication as well. Being in touch with my body is such a wonderful feeling and I feel much more in control of not only my fertility but also my life."

Amanda, Stay at Home Mom

"I have already recommended the product and two of my friends have bought Daysy! I love it! I personally dislike birth control pills. They make me.... well, not me. Other birth control methods I have heard first hand horror stories. That one story of each product makes it not worth the risk to me. This is extremely easy to do and extremely easy to remember to do. I use my cell phone as my alarm to wake up, and I keep Daysy on my night stand right next to my phone. I have been using it for the past 7 months and I love it!"


"I would absolutely recommend daysy. I am very conscious of what I put into my body, so when I started researching the pill I knew it wasn't the form of birth control I wanted to use, and I wanted to use a natural form of birth control and trust my body. I thought tracking my cycle would be complicated, but Daysy makes it so easy! Right now, I'm not planning for a baby but I know Daysy will be just as helpful in that stage of life as Daysy is right now."

Brooke, Preschool teacher

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You can rely on Daysy.

The fertility monitoring algorithm in Daysy has been developed with feedback from millions of cycles and uses advanced statistical methods to calculate your fertility status.

Daysy's program relies on the Lady-Comp algorithm. The Lady-Comp, is the most popular fertility tracker internationally.

The fertility tracker is programmed to accurately determine and display the time of ovulation in the female body by taking your daily basal body temperature.

  • Red = fertile
    Red days are when to plan for a baby.
  • Red blinking = ovulation day
  • Green = infertile
    Green days will not lead to pregnancy.
  • Yellow = learning phase/cycle fluctuations
    Daysy needs to learn more about you. If preventing pregnancy, treat as red days.
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Daysy has an App.

Simply connect your Daysy fertility calculator to DaysyView to see all your cycle data.

Once Daysy is connected to her app, you can start syncing data with DaysyView.

DaysyView lets you see your temperature data and fertility prognosis.

Share your data with your loved one, and let them know when it’s the “right” day.


Meet DaysyView.

  • See your daily, weekly and montly status of fertility
  • See your color - coded monthly calendar
  • Make notes
  • See your cycle forecast
  • See your temperature curve and values
  • See your fertility and cycle statistics
  • Share your data with your loved one through DaysyView Partner App
  • Enter sexual intercourse
  • Get notified when something changes in your cycle
  • Contact our expert team for advice and support
  • Get free cycle analysis

The medical basics of a woman's cycle


Every woman is different,

but these are the basic physiological factors to a woman's menstrual cycle that you should know:

  • Every woman usually only ovulates once per cycle.
  • If two or more ovulations take place, these would occur within 24 hours.
  • After ovulation, the egg can be fertilised for a maximum of 18 hours.
  • Inside the female body, sperm remain able to move and fertilise for a maximum period of 5 days.

This means that a pregnancy can occur on only 6 days, which are the 5 days prior to ovulation and the day of ovulation itself. Daysy calculates these 6 days and displays them to you.


Exactly how does the fertility calculator Daysy work?

Daysy recognizes a woman's ovulation in her cycle through a morning measurement of the basal temperature. Simply measure the temperature under your tongue to know whether you are currently fertile or not. Depending on the phase of your cycle, you will either see a green light or a red light.

Beyond that, Daysy records the course of your cycle and shows you which processes are currently taking place in your uterus. There is hardly a simpler way to attain awareness of your female body.

When comparing Daysy to your alternatives, what makes this cycle monitor so special is that it bears no side-effects: no hormones, no thrombotic risk, or any other accompanying effects. It does not get any better than that!

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