NER Cycle App

This app helps you track menstrual-cycle symptoms day by day and evaluate
your records manually following the NER rules (Rötzer), in the spirit of
INER.

The evaluation stays with you: you place every mark on the cycle chart
yourself. The app only does the arithmetic you would otherwise do by hand
— the baseline drawn from the six prior low measurements, counts, lines,
and statistics (cycle and phase lengths). It computes and displays; it
never suggests and never decides. For a reliable interpretation of
fertility you need knowledge of the method — from a textbook or a course.

The app is in beta: storage and evaluation are stable, but screens,
controls, and features are still being revised, and the name, icon, and
colour scheme are not final. Data loss cannot be ruled out entirely —
export your data regularly and before every update via Export in the
settings.

Features:

• All your data stays on the device — no cloud, no analytics, no network
permission.
• Language: German and English — follows your system language or can be
switched in the app.
• Daily entry of basal body temperature (with exclusion flags for
disturbances such as illness, alcohol or a late bedtime), bleeding,
cervical mucus in the NER shorthand notation (t, Ø, f, S), optional
cervix, pain, sexual intercourse, and notes.
• Evaluation tools: first temperature above the baseline, count of low
measurements, mucus peak day, sympto-thermal fertile window, exclusion
of disturbed days.
• PDF export: export the evaluation as a print-ready PDF.
• Import from Drip: bring in existing data from the Drip app (CSV export).
• Export and Import in the settings — your data always stays
your own.
• Open source; licensed under Apache-2.0.

Note: "NER Cycle App" is a working title; the final name has not been
chosen yet.