Daysy
Daysy Fertility Tracker.
A hormone-free way to understand your cycle more clearly.
Product highlights
Everything you need to know about your cycle.
Expected ovulation
Detected ovulation
Fertile & non-fertile days
Menstruation tracking
Expected menstruation
Notes & cycle statistics
Daily temperature insight
How it works
Three simple steps.
Measure
First thing in the morning, place Daysy under your tongue for 60 seconds before getting up.
Confirm menstruation
Mark menstruation days directly on your device with a single button.
Sync when you choose
Sync to the DaysyDay app whenever you want — your data stays with you.
Device & app
Your data, on your terms.
Every measurement is stored securely on your Daysy device. When you're ready, sync to the DaysyDay app to see the bigger picture — and pause syncing whenever you like.
Calendar view
See fertile, non-fertile and menstruation days at a glance.
Temperature curve
Visualise your basal temperature across the full cycle.
Cycle statistics
Track patterns, lengths and trends over time.
Free Partner app
Share what you choose. Nothing more.
A free partner app lets your partner stay informed and supportive — but only with what you choose to share. You stay in control of every detail.
- You decide what your partner sees
- Permission-based visibility, always
- Privacy-first by design
Why women choose Daysy
A calmer, clearer relationship with your cycle.
Hormone-free
Nothing in your body. Just observation, every morning.
Insightful
Understand fertile windows, ovulation and patterns over time.
Easy to live with
60 seconds in the morning. Fits a health-conscious lifestyle.
Cycle awareness
Build a deeper understanding of your body, month after month.
Reliability
Built on precision and science.
Scientific study
Daysy's accuracy has been examined in a peer-reviewed study.
Precise sensor
Measures basal temperature to 1/100°C — engineered for fine shifts.
Smart algorithm
An internal algorithm refined over a decade of cycle data.
Ready to understand your cycle?
Hormone-free, privacy-first, and made to last.