Cycle tracking, due dates, and fertile windows.
Pregnancy due date, ovulation window, menstrual cycle calendar — three calculators rooted in well-established clinical formulas (Naegele's rule for due date, the standard 14-day luteal phase model for ovulation). Each runs locally; nothing uploads. These tools support self-tracking and education — they aren't diagnostic and don't replace professional medical advice.
Estimate due date, gestational age, and trimester from your last menstrual period (Naegele's rule).
Find your expected ovulation date and fertile window based on your last period and cycle length.
Project your next six menstrual cycles on a calendar grid from a single last-period date.
Naegele's rule is a population estimate; ultrasound dating in the first trimester is more accurate.
Less so. Methods that assume a 28-day cycle err when actual length varies.