Stay connected
to your cycle
Clinically proven to predict your fertile days, based on the science of your temperature.
How it works
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 & 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
NC°
The Pill
IUD
Typical use effectiveness rates. Source:
Contraceptive Technology (Table 5-2). 22nd Edition, 2023
Cyclers say it best
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 learnt 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 cleared by the FDA as birth control. Most other fertility apps assume your cycle is 28 days long. This means the fertile window they predict is not personalized to your cycle. So how can it be true to you? Our algorithm significantly lowers the risk of you receiving an incorrect fertility status since it uses your unique temperature data, which reduces the risk of unwanted pregnancy and can even help you plan for pregnancy with greater precision.
Not all period trackers keep secrets — some might even share them. With the Natural Cycles app, your data stays yours. We provide an advanced data privacy protection program designed to keep your data safe.
Find out why more women than ever are choosing 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.
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.
FDA Cleared
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.