Chart the Creighton Model, on every device.
Chart35 turns your daily observations into a clear CrMS chart - peak day, cycle length, and stamps - and keeps it in sync across your phone, watch, and the web.
Web app in your browser, or install via TestFlight (iOS) and Google Play (Android).
Everything you chart, nothing you don't
Built around the Creighton Model as it's actually taught - the stamps, the peak day, and the rules you learn from your FertilityCare Practitioner.
Daily observations
Record bleeding, mucus, and the CrMS observation codes as you go. Chart35 builds the standard stamp for each day automatically.
Peak day & cycle analysis
Your peak day, post-peak count, and cycle length are calculated for you, with a trend view across cycles.
End-to-end encrypted sync
Your chart is encrypted on your device before it ever leaves it. We can't read your data - only you can.
Share with your practitioner
Send a read-only link to your FertilityCare Practitioner or doctor. No account needed on their end.
Phone, watch & web
Log an observation from your Apple Watch, review on your phone, print from the web. It stays in sync.
Works offline
It's a full offline-first app. Chart on a plane or in a basement clinic; it syncs when you're back online.
Your fertility data stays yours
Chart35 encrypts your observations end-to-end. The chart, the codes, the notes - all of it is unreadable on our servers. Export it as JSON or CSV anytime, and delete your account and cloud data whenever you want.
How it works
The same routine you already follow, made faster.
Observe
Make your observations through the day, the Creighton way.
Record
Tap in the day's most fertile sign and any notes. Chart35 assigns the stamp.
Review
Watch your peak day and cycle take shape, with insights across cycles.
Share
Send a read-only chart to your practitioner when you follow up.
About the method. The Creighton Model FertilityCare System (CrMS) and NaProTECHNOLOGY were developed at the Saint Paul VI Institute. Chart35 is an independent app for keeping your own chart; it is not affiliated with, endorsed by, or a substitute for the Saint Paul VI Institute, Creighton University, or FertilityCare Centers of America. Chart35 helps you record and review your observations - it does not teach the method or interpret your chart for you. To learn the system and its rules, work with a trained FertilityCare Practitioner.