Learn to read your own cycle.

Each morning you log your waking temperature and what you observe: cervical fluid, flow, tests, anything else worth noting. Thirty seconds, most of it the thermometer. Lutaria draws your chart, finds the temperature shift that confirms ovulation, and brackets your fertile window using the same sympto-thermal rules taught by fertility-awareness educators for decades.

After your first full cycle, predictions stop using textbook averages and start using yours: your cycle length, your luteal phase, your patterns. And when you want the chart explained in plain language, one tap gets a clear summary of what your body is showing, whether you are trying to conceive, avoiding pregnancy, or simply paying attention.

Every rule behind those numbers is written down: see how the math works.

On your phone or computer, in your browser's own storage. Saving an entry makes zero network requests; you can watch the network tab and see for yourself. Our servers hold your email for login and a handful of preferences, your goal and your timezone among them. Nothing you log is on that list, unless you choose otherwise.

Optional sync between devices is end-to-end encrypted with a passphrase only you know. What reaches us is ciphertext we cannot read, cannot sell, and cannot be compelled to decrypt. Export everything as JSON or CSV anytime; erase everything with one tap. The details live in the what we can and can't see popup.

Charting is a skill, and most people learn it faster with help. Lutaria members can connect with approved fertility-awareness mentors: certified educators and experienced charters, each reviewed personally before approval. You connect with a mentor's code, share exactly the charts you choose, and chat inside the app. Nothing is visible to a mentor until you explicitly share it, and you can end the connection anytime.

Teaching charting yourself? Create an account and apply from the Mentor tab.

Lutaria imports the CSV export from other charting apps directly: temperatures, fluid observations, cycles, notes, and custom entries carry over in seconds, and your history immediately powers your predictions. JSON restore covers moves between your own devices.

The name comes from the corpus luteum, Latin for “yellow body”: the small gland that forms in the ovary right after ovulation. It produces the progesterone that raises your resting temperature, the very shift the chart looks for, and its lifespan sets the luteal phase your predictions are built on. The golden dot in the icon is it.

It is not a medical device, not medical advice, and not a contraceptive. Charts and predictions are educational estimates built from data you enter. If you are making decisions about preventing pregnancy, work with a healthcare provider or certified educator on a method appropriate for you; if you have been trying to conceive without success for a year (six months if 35 or older), talk with a doctor.

Email hello@lutaria.com. A person reads it.