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 - with an accuracy of 99.4%. Your fertility status will be displayed either as 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.

"Daysy allows me to take control of my cycle without hormones or side effects. I can use Daysy and not have to worry about making errors the way I would with the calendar or mucus method alone. I can be confident that I am understanding my body well and being responsible with my future!"

Anonymous, high school math teacher:

"I would say that daysy is one of the most fantastic purchases I have ever made! It has taught me to listen to my body and its natural cycle rather than changing it with unnatural methods. I would most definitely recommend this product to my best friend, in fact, I have! "

Natalie, student

"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 wanted to share my experience now that I've used Daysy for a full month.

The post on Daysyusa's Instagram page saying "You don't ovulate on the same day every cycle" was spot on and I felt the need to share how much that resonated with my experience.

I have a very regular cycle. I track my BBT and CF daily and know that I ovulate on Day 14 like clockwork... except this month I was traveling and experiencing a bit more stress than usual. This is our first month TTC and when Daysy indicated I ovulated on Day 16 rather than 14, we acted accordingly.... just found out I am pregnant today!

Daysy is a revolutionary product and I have been telling my patients, colleagues, friends, and family all about it! Very impressed!"

Anonymous until Announcement

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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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