How does Natural Cycles work?

Natural Cycles is an app powered by an algorithm that determines your fertility status based on basal body temperature. Just measure with your NC° thermometer, enter it into the app, and let our algorithm do the work.

couple lying down with pillows, a thermometer and a smartphone

How to use Natural Cycles

Measure your temperature and add data

When you wake up, measure your temperature using your basal thermometer and add the reading into the NC° app.

Wait for the algorithm to calculate your fertility

Our algorithm uses temperature, period, and cycle data to quickly see if today is green (not fertile) or red (use protection).

Know your fertility and take control of your cycle

Your daily fertility status can be used to plan or prevent pregnancy. Plus, you’ll receive tailored insights into your own unique cycle.

How BBT works

Basal body temperature (BBT) is the body's lowest resting temperature. You can measure it first thing in the morning when you wake up. BBT changes during the menstrual cycle and can be used to detect ovulation and identify your fertile window. You don't need to measure BBT every single day, but building a routine of measuring most mornings helps the algorithm get to know your cycle.

How our algorithm works

Natural Cycles is more than a fertility awareness method. It’s powered by a regulated and certified algorithm that learns the pattern of your unique cycle to work out each daily fertility status.

See how the algorithm works:

Your cycle starts on the first day of your period. Ovulation happens around the middle of the cycle, but this day can change depending on the pattern of your cycle.

How to use the Natural Cycles° app

Read your daily fertility status

After adding your temperature, you will get your fertility status for the day. This is either green (not fertile) or red (use protection). If trying to prevent pregnancy, you should use condoms or abstain from sex on red days.

Track PMS, pain & more

Add optional data throughout your cycle including changes to mood, sex drive, PMS and pain. Tracking symptoms can help you learn even more about your unique menstrual cycle.

Understand your cycle

Our popular graph feature helps you identify patterns in your cycle. You can also view the symptoms you have logged. Easily compare cycles or zoom out for an overview.

Adapt your fertility journey

Natural Cycles is a long-term fertility partner. Switch between NC° Birth Control, NC° Plan Pregnancy and NC° Follow Pregnancy depending on your journey.

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

Discover Natural Cycles° today