How does Natural Cycles work?

Backed by science, the NC° algorithm is powered by body temperature.
Woman holding Natural Cycles App

How to use Natural Cycles

Measure your temperature

woman sleeping with Natural Cycles

Choose your device and measure either overnight or in the morning.

Open the NC° app

woman looking at her data with Natural Cycles

The algorithm behind the app is analyzing your body temperature.

Confirm your fertility status

Woman holding Natural Cycles app in her hands

At a glance, know if today is a Green Day (not fertile) or a Red Day (use protection).

Body temperature and the cycle

Our hormones cause body temperature to rise around ovulation. By analyzing this we can pinpoint where you are in your cycle.

A method that’s tailored to you

Not only can we confirm ovulation but we can predict it, based on your unique cycle.

See how the algorithm works:

visualisation of a menstrual cycle with period and ovulation marked

Your cycle starts on the first day of your period. Most of us aren’t fertile at this time so you will get Green Days.

visualisation of the menstrual cycle showing the 6 day fertile window

As ovulation approaches you enter the fertile window. Now the algorithm gives only Red Days since there is a risk of pregnancy.

visualisation of the menstrual cycle showing the temperature rise after ovulation

After ovulation your temperature rises, as you are no longer fertile. The algorithm will give you Green Days once again.

visualisation of the menstrual cycle showing red and green days

The amount of Green Days you get will increase over time as the algorithm gets to know your cycle better and better.

See how the algorithm works:

Inside the NC° app

Main Screen

View your fertility status

It's easy to see if today is a Green or Red Day so you know if you need to use protection.

Temperature Screen

Track and learn more

Monitor emotional and physical symptoms to learn about the changes in your body.

NC Graph

See the bigger picture

Spot patterns and compare previous cycles with your graph view.

Natural Cycles modes

Adapt your fertility journey

Smoothly switch from preventing to planning, pregnancy, and postpartum, NC° supports you every step of the way.

Read more about NC° Birth ControlRead more about NC° Plan Pregnancy

Go hormone-free today

Start my journeyWill it work for me?