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Stay connected
to your cycle

The only FDA-cleared birth control app

Clinically proven to predict your fertile days, based on the science of your temperature.

How it works

1

Sleep with your Apple Watch

Track temperature trends in your sleep with your compatible Apple Watch.

For each stage of your journey

NC° evolves with your life and goals.

Hormone-free, FDA-cleared birth control. Know your fertile days and when you need protection.

Know your peak fertility to increase your chances, then track changes and baby’s growth.

Support after birth. Monitor your cycle’s return and track your recovery at your own pace.

Understand your body’s changes, recognize symptoms, and feel prepared and in control.

How effective is
NC° Birth Control?

98% when used as intended,
93% with typical use.

NC° is in the same effectiveness category as
the pill with zero side effects.

Condom

87%

NC°

93%

The Pill

93%

IUD

>99%

Typical use effectiveness rates. Source:
Contraceptive Technology (Table 5-2). 22nd Edition, 2023

Cyclers say it best

4.8

58K+ global rating

Dr. Katara

Joined in 2021

Has got to be THE best natural birth control on the market. 10/10 recommend!

Shadow

Joined in 2019

NC° helped me understand my body, cycle, and the best time of the month to get pregnant.

Michelle

Joined in 2022

I feel empowered knowing about my body’s natural processes.

Chlöe

Joined in 2022

I feel safe and secure with NC and have learned more about my cycle and body through the app.

Allison

Joined in 2025

I love the educational messages I receive that allow me to take my knowledge to the next level.

The most studied app of its kind

FDA cleared

for 8 years

Certified in

35+ countries

30 studies

published 

Track your fertility in your sleep

Common Questions

Natural Cycles can be used with Apple Watch Series 8 and later, any model of Apple Watch Ultra, and Apple Watch SE3. Please note that the Apple Watch SE & SE (2nd generation) models do not have temperature sensors, so they can’t be used with Natural Cycles.

The hormonal shifts that are linked to your body temperature are so small they can only be detected while you’re resting. To get the most out of Natural Cycles you should wear the watch for at least four hours a night for five nights a week.

Natural Cycles is the first and only app of its kind to be FDA Cleared and CE Marked. Most other fertility apps assume your cycle is 28 days long. This means the fertile window they give you is not personalized to you. Our algorithm significantly reduces the risk of you being assigned an incorrect Green Day as it uses your personal data. This reduces the risk of unwanted pregnancy or can help you plan pregnancy with greater precision. 

While some fertility apps make money from selling data for advertising, we never have, and never will sell our users’ data. Find out why women around the world choose Natural Cycles.

Yes, you can use Natural Cycles with an irregular cycle, and it's just as effective. Natural Cycles captures your unique cycle patterns by considering cycle irregularity, temperature fluctuations, recent use of hormonal contraception, ovulation day variation, sperm survival, and several other essential factors to provide a tailor-made solution for each individual.

Checkout this article for more information about using NC° with irregular cycles.

Natural Cycles is a regulated medical device that follows GDPR and is designed to keep your data safe with the highest level of security and encryption. Protecting user information has always been a top priority for Natural Cycles. Now more than ever, sensitive data requires greater protection and regulation, which is why you can rest assured knowing that we are committed to protecting your information. Visit our data security page to learn more.

Yes! If you don’t have Apple Watch, you can still make the most of our hormone-free birth control. You can choose to measure overnight with the NC° Band or another compatible device.

You must be over the age of 18.Does not protect against STIs.

Natural Cycles is 93% effective with typical use, 98% effective with perfect use. No method of contraception is 100% effective. Natural Cycles does not guarantee that you cannot get pregnant; it only informs you whether and when you can become pregnant based on the information that you enter into the application.

Natural Cycles is available as a method of birth control in the US and territories; Canada; United Kingdom; Ireland; France; Germany; Netherlands; Luxembourg; Belgium; Spain; Portugal; Austria; Switzerland; Italy; Latvia; Lithuania; Malta; Estonia; Sweden; Denmark; Norway; Finland; Iceland; Bulgaria; Czech Republic; Hungary; Poland; Romania; Slovakia; Greece; Cyprus; Croatia; Slovenia; Montenegro; Singapore; Australia; Brazil. Outside these countries listed, Natural Cycles is intended to be used for fertility monitoring.