Period & Fertility Calculators & Trackers
Private cycle tracking and date estimates with clear uncertainty and no contraception claims.
Estimate the next period date from recent cycle lengths or the last start date, showing uncertainty rather than a single guaranteed date.
Open tool →◌Period TrackerStore observed period dates locally, derive cycle statistics and forecasts on-device, and keep estimates visually separate from observations.
Open tool →◌Cycle Day CalculatorCalculate cycle day from the last period start date and a target/current date using date-only arithmetic.
Open tool →◌Cycle Length CalculatorCalculate individual cycle lengths, average, median and variability from at least two period-start dates.
Open tool →◌Menstrual Cycle CalendarShow observed and estimated cycle dates in a private local calendar with different visual treatment.
Open tool →◌Ovulation CalculatorEstimate ovulation from the expected next period minus an editable luteal-phase assumption and show the assumption used.
Open tool →◌Fertile Window CalculatorEstimate a broad fertile window around ovulation and explicitly state that the result is not contraception.
Open tool →◌Luteal Phase CalculatorCalculate luteal-phase length from an observed/estimated ovulation date and next period start.
Open tool →◌Pregnancy Test Date CalculatorEstimate an earliest/recommended pregnancy-test window from expected period or ovulation timing and defer to test instructions.
Open tool →◌Implantation Date CalculatorShow a broad estimated implantation window from ovulation/conception timing and emphasize uncertainty.
Open tool →◌Conception Date CalculatorEstimate conception date or range from LMP, due date or ovulation and clearly label the chosen method.
Open tool →