Daysy

Natural family planning for women ready to take matters into their own hands

Tired of feeling spaced out and on edge? Or jumping between methods without finding the one that works for you?

Regain control, feel more in tune with your body, and get a window into your overall health with the fertility awareness method. Without tracking tons of signs like cervical mucus.

Here's how it works

Meet your new best pal, Daysy

Planning pregnancy? Postponing pregnancy? 
Daysy’s got you through it all.

Wake up and take your temp
Each morning before getting out of bed, take your basal body temperature under your tongue. It just takes a minute. Literally.

Your info syncs automatically
You don’t need to enter your temperature into the app (and risk making a mistake that could lead to an unplanned pregnancy). It transfers via Bluetooth.

No wifi? No problem
Your cycle works as usual when you’re off the grid – so should your tracker.

Daysy functions as a standalone device without internet. So you’re always in the know about your fertility.

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See your fertility status in under 60 seconds per day

Works with irregular cycles

Identifies fertile and non-fertile days with 99.4% accuracy

Our science

Your fertility is serious business. You deserve only the best.

Certified medical quality you can trust

Daysy is a registered medical device according to EN ISO 13485.

All of our devices are produced in Germany, inspected by the FDA, and undergo extensive testing by certified third-party agencies.

Smart algorithm that adjusts to you

Other fertility tracking algorithms use AI and guess when irregularities are detected.

Daysy’s algorithm considers your past average temperature and can handle occasional outliers to tell you when you’re fertile and not.

If there isn’t enough data to give you a red (fertile) or green light (not fertile) with certainty, Daysy will display a yellow light (learning or cycle fluctuation). Because your fertility is not a guessing game.

Sensitive and precise sensor

With basal body temperature, the slightest change can make all the difference.

Unlike other BBT thermometers, Daysy combines a sophisticated sensor and an algorithm with 35+ years of development. She measures to a hundredth of a decimal point (+/- 0.018 °C) to detect hormonal fluctuations during your menstrual cycle. All in under 60 seconds.

Robust tech that lasts years

Invest in a lifetime of cycle tracking with Daysy. Many women in our community have been using Daysy for over 10 years.

“The only thing that saddens me is that I didn’t discover it years ago”

...and more reviews from happy Daysy users

Find out why 99% of Daysy users would recommend Daysy to a friend.

After using Daysy for several years alongside my own charts (just for fun, because I'm nerdy enough to find chart-making fun), I’ve never had so much as a "scare." Plus, seeing how its calculations always align with my own, I feel confident enough to keep using it. I’ve had great results relying on Daysy for both contraception and achieving two pregnancies. It takes about 30 seconds of my day and I am happy knowing I’m not messing with my hormones. After about five years of using my Daysy, I couldn’t be happier with it. It’s easy to use, it doesn’t turn me into a jerk, and it works. That’s really all I want from a birth control method, and, so far, Daysy delivers.
Sarah
Comes with a free App

So much more than a period tracking app

Get pregnant faster

Skip the stress, self-doubt, and months of waiting and wondering. 

Track your fertility daily with Daysy and learn if you’re ovulating, 

if you have regular cycles, and exactly which days are best for conception.

 

In a survey of Daysy users, 63% reported they conceived the first cycle they tried. And 89% reported they conceived within just 3 months with Daysy.

I love Daysy: I have used the Daysy for 4 years now. I was not sure at first but felt like hormonal birth control was no longer for me. I am so grateful I gave Daysy a shot. I was able to avoid pregnancy when I wanted and I was able to get pregnant right when I wanted two different times. I can’t say enough positive things about it. It’s easy to use, accurate and the staff is great with any questions. I would definitely recommend this product.
Tara Lynn
To prevent and then plan pregnancy! I used Daysy for over a year to prevent pregnancy, and after the year we wanted to try for a baby. With the help of Daysy we conceived immediately and now I am 12 weeks along! I cannot recommend it highly enough
Jennifer
Who this is for

Got a period? You can use Daysy.

Menstrual cycles between 19 and 40 days

Irregular periods

Irregular sleep schedule

Shift workers

Postpartum mothers

You don’t have to live a certain type of lifestyle or avoid alcohol to use Daysy to track your fertility.

Us vs. them

See how our cycle trackers stack up

Lady-Comp Daysy Other period trackers
99.4% accurate 99.4% accurate 93% accurate
No app needed Works without an app Needs both a thermometer and app
One-time purchase, no hidden costs (payment plans available!) One-time purchase, no hidden costs (payment plans available!) $9.99+ monthly subscription
Works offline Bluetooth only on demand Needs wifi to display fertility status
Reliable algorithm that works with irregular cycles Reliable algorithm that works with irregular cycles Algorithm uses AI to fill in the gaps
Long battery life Long battery life Needs phone charger
Backlit display Lights up with fertility status No backlit display
Sensitive sensor that measures to the hundredth of a degree Sensitive sensor that measures to the hundredth of a degree Sensor only measures to the tenth of a degree
Detects hormonal deficiencies - -
Shows expected delivery date - -

So many ways to save

FSA and HSA eligible

Get reimbursed for your device through your health insurance.

Payment plans available

Starting at just $20 per month or 0% APR with affirm.

Refer a friend to save 10%

Got a friend who’d love this? You’ll each get a code to save.

Hear from more happy Daysy users

Absolutely love it: I’ve been using Daysy for two years now and absolutely love it!! It’s so easy to use, I love the lights that flash according to your fertility status.
I’ve gone 3 months without needing to charge it! Daysy has been super accurate with everything so I confidently use it to avoid pregnancy, once I start that chapter of my life it’ll also be nice to use daysy to actually aid in conceiving. I love how it stores my temperature and then saves it on my daysy app once connected without needing to enter it manually. It’s a bit of an investment up front but you have 0 monthly fees and they’re their customer service is extremely helpful! I highly recommend daysy to any woman who would like an alternative to hormonal birth control.
Jenn Z

You don’t have to measure at the same time everyday - plus more answers to smart questions about Daysy

What is the best way to measure?

For optimal use of Daysy, we recommend that you should have slept sufficiently (at least one hour) before the measurement. It is important that you take your temperature immediately after waking up, before getting up and becoming active. Measure below your tongue, with your mouth closed, and keep the device steady while it is measuring. Video Tutorial

Do I have to measure at the same time every day?

No. You should have at least one hour of good quality sleep before the measurement. It is important that you take your temperature immediately after waking up, before getting up and becoming active. For optimal use of Daysy, try to get at least 3 or more hours of sleep before measuring. Less sleep can result in more temperature fluctuations causing Daysy to give more fertile or potentially fertile days.

How do I enter or edit menstruation?

You can confirm or remove menstruation at any time during the current day. Simply press the button to turn on your Daysy, and then press and hold the activation button until the violet light lights up without flashing and you hear a "beep." Confirm you are menstruating for each day of active bleeding and for a minimum of three consecutive days. You can also remove menstruation data for the same day by turning Daysy on and pressing and holding the activation button until the purple/blue light is no longer solidly lit and begins flashing again.

Video Tutorial

How long until Daysy knows my personal cycle?

The first 2-4 cycles of use are considered Daysy's learning phase. Over the course of her learning phase, Daysy will come to understand your cycle and begin narrowing down your fertile window. Daysy remains quite cautious and conservative during this time, which is why Daysy is accurate starting the very first day.

When can I start to rely on Daysy's results?

You can rely on Daysy's results starting the very first day of use. In the beginning, you will see more yellow and red days because Daysy is still learning your unique cycle. You will see more green days as Daysy comes to understand your cycle and can narrow down your fertile window. The more regularly you measure, the better.

My cycle is irregular. Can I still use the devices?

Yes. Irregular cycles are not a problem for Daysy/Lady-Comp. Even with irregular cycles, all Valley devices distinguish between non-fertile and fertile days with a very high accuracy. However, in case of extreme fluctuations between cycles it will give you more red and yellow lights and less green lights. Fluctuations of several days are usually not a problem. If you have questions about your unique cycle, please reach out to our team of experts.

Are there any costs associated with the DaysyDay app?

No! DaysyDay is free! There are no in-app purchases or upgrade fees.

Does illness reduce the reliability of the device?

In general, you should skip measurements during illness and while you are taking medication that can have an influence on your body temperature or cycle. If you have doubts, contact your doctor or our customer service team.

More: Contact