Fertility and Period Tracker for iPhone

Estimating your most fertile days

There are multiple ways to estimate when you are most likely to conceive. One commonly used approach focuses on ovulation timing — identifying the days around ovulation when fertility is highest. This guide describes that ovulation-based method and how a fertility app can help.

What you’ll need to set up a tracker

• A free version of the app or service for basic tracking and predictions
• The KMOH utility or module if you want its specific features
• A recommended paid alternative for more advanced options and support

How the app determines fertile days

The app uses an algorithm centered on ovulation to predict your fertile window. It applies a scientific framework developed by Rodrigo Guerrero that pinpoints the days when conception is most likely. The system combines that theory with user-entered cycle data to estimate high- and low-fertility days for each cycle.

Evidence and future updates

The underlying method has been validated by hundreds of thousands of users, lending practical support to the theory. Some related scientific studies are still pending publication; when new, peer-reviewed findings are released, the application will be updated to reflect the latest evidence.