How trackle works

trackle is a system that helps you to understand your cycle. With trackle you can determine whether you are currently fertile or not. trackle consists of an app, a calculation system and a sensor. 

The trackle sensor measures your core body temperature. The trackle app transmits the core body temperature and records your input (cervical mucus, cervical os position, etc.). Based on your input and your core body temperature, the trackle system calculates whether you are currently fertile or infertile.

The trackle sensor

trackle measures your core body temperature while you sleep. For this purpose, the approximately tampon-sized sensor is inserted vaginally at bedtime. There it measures your body core temperature at regular intervals and saves it – it does not take up radio communication.

When you remove it in the morning and place it in its box, it connects to the trackle system via your mobile phone and transmits the stored data. There, the temperature data (and the other parameters such as bleeding time, cervical mucus quality, etc.) are calculated. The app then shows you the result: on the home screen the fertility status of the current day, the prognosis for ovulation and the next menstruation. In the calendar screen you will find these informations per day – here you also enter yourself, whether you want to exclude a day out of the rating, what observations you have otherwise made etc.

What are the benefits of overnight measurement?

trackle measures your body core temperature while you sleep – every minute. From this series, the system uses the lowest value for calculation – the surface temperature or basal body temperature.

That’s the big difference compared to punctual measurement in the morning with a usual thermometer: it doesn’t matter when you sleep, whether you work shifts, have little children, went to a party: as long as you sleep 4 hours, trackle determines your temperature.

You don’t have to take your temperature at the same time every day, and the value is not so easily distorted by your daily routine and environment. This makes a decision for Natural Family Planning much easier. 


The sensor has a battery for energy supply and lasts for two years. Then you can send it back to us – and if you like, you order a new one.trackle is a certified medical device and is subject to strict quality criteria. The outer material of the sensor is medical grade silicone, the battery is approved for use in the body. trackle has been extensively tested in external laboratories. 

Data protection plays an important role for us – we do not ask you for more information than is absolutely necessary. The data is already signed and encrypted when transferred. Our customer support will be happy to answer any conceivable question, you can reach us by email at [email protected].

The trackle app

Recognize fertile days quickly

The trackle app shows you whether you are currently fertile or not.
On the start screen of the trackle app you can see the fertility status of the current day, the forecasts for ovulation and the next menstruation.
The red colored area is the time of your menstruation. The green period shows the fertile days. And what is grey shows you the infertile period.
At the beginning of your cycle, you see prognoses. As your cycle progresses, the forecast will be “readjusted" daily.

Tracking and understanding your cycle

It’s your turn with the calendar: in addition to the automatically transmitted temperature values, you enter your other cycle observations here: cervical mucus, menstrual bleeding – and anything else you find remarkable for your own body logbook.

In retrospect, you will certainly notice many different correlations: You always have a headache around ovulation? Or a bad mood due to PMS? Your hair looks perfect – this must be the first half of the cycle?

Who tracks, understands!

Decide for yourself

We believe: You have a right to understand what happens when in your body. Proven calculation methods, valid data collection, tested safety – these are the ingredients from which trackle mixes your decision basis. And what will you do with it? Decide for yourself!

How does trackle evaluate?

trackle evaluates your cycle using the rules of the temperature method

The symptothermal method combines the observation of core body temperature and cervical mucus for cycle evaluation. 

trackle calculates your ovulation as soon as there is a rise in your core body temperature and your cervical mucus evaluation is complete. 

trackle recognizes your ovulation and tells you whether you are currently fertile (green) or infertile (white).

You can find a legend of the cycle curve here.

Surface temperature

The core body temperature increases by about 0.2°C as soon as you ovulate. trackle recognizes that increase if you have measured elevated core body temperature for at least three consecutive days.
Tip: Start measuring every night right after your period and continue until your ovulation has been determined.

Cervical mucus

The cervical mucus changes during the cycle: the closer it gets to ovulation, the more elastic and transparent it becomes. Shortly before ovulation the cervical mucus reaches its best quality, the cervical mucus peak. When your ovulation has occurred, the cervical mucus becomes murky and lumpy again. For the evaluation trackle needs your cervical mucus climax and then cervical mucus of poor quality for three days.

Tip: Observe your cervical mucus every day. In the evening you enter cervical mucus with the highest quality into the app!

Developed by a woman

Made in Germany

medically approved

Test trackle and learn more about your body!

trackle combines your core body temperature measured overnight with your information on cervical mucus and thus determines your fertility status precisely. You can order trackle from us and return it for three months if you do not like it. Our support will be happy to answer all your questions at [email protected]. We are looking forward to you!