Fertility Module
Plan Your Pregnancy
Ovulation tracking, fertility windows, cycle analysis, and conception tools - everything you need when trying to conceive.
Ovulation & Fertility Tracking
Know your most fertile days
Ovulation Calculator
Predict your ovulation day from your cycle length and see the six-day fertile window that ends on ovulation itself — the window Wilcox 1995 measured.
Fertility Window Tracker
Daily fertility status - low, high, or peak. Know the best days to try.
Cycle Length Calculator
Track your cycles over time. Calculate averages and identify irregularities.
Conception Planning
Tools to help you conceive
Conception Date Calculator
Estimate when conception occurred based on your due date or last period.
Implantation Calculator
Track the timeline from ovulation to implantation to when you can test.
Due Date Calculator
Calculate your estimated due date based on conception or last period.
Fun Predictors
For entertainment only
Chinese Gender Predictor
Ancient Chinese method using lunar age and conception month.
Mayan Gender Predictor
Mayan calculation based on age and year of conception.
Zodiac Sign Planner
Plan conception timing for your preferred zodiac sign.
Sibling Age Gap Calculator
Calculate the age gap between siblings based on due date.
Fertility Planning FAQ
Common questions about fertility tracking
Log a basal temperature shift, a positive ovulation test or egg-white mucus and the app re-centres your fertile window on the confirmed ovulation day — the calendar estimate alone never moves it.
Yes! The app adapts to irregular cycles and uses multiple data points including OPK results and symptoms to improve predictions.
No, OPK logging is optional. The app calculates fertility windows from cycle data alone. OPK data improves accuracy when available.
Yes. Logging intimacy is opt-in and off by default, and it is never carried into the doctor PDF. If you share with a partner, they see one summary row — cycle day and last period start — never your flow, symptoms, intimacy or notes.
When you switch to the pregnancy side, your cycle length and period length carry over, so your due-date and conception calculators start from your own numbers instead of a 28-day default.
Start Your Fertility Journey
Download ProbaBaby for free fertility tracking tools.
- Free to download
- No subscription
- 32 free tools