Pregnancy Chance Calendar

Welcome to the Pregnancy Chance Calendar, your go-to resource for tracking menstrual cycles, predicting fertile windows, and estimating daily pregnancy probabilities. Whether you’re actively trying to conceive or simply gaining insights into your fertility patterns, this calculator provides personalized cycle predictions based on your unique cycle length and recent period start date.

How to Use the Pregnancy Chance Calendar

1. Navigate Months:
   • Use the left and right arrows at the top of the calendar to move between months.
   • The year updates automatically when you move past December or before January.
2. Set Your Cycle Length:
   • In the “Cycle Length” field, enter how many days your menstrual cycle typically lasts (e.g., 28 days).
   • This number helps calculate when your ovulation is likely to occur and how the rest of your cycle might unfold.
3. Mark the Start of Your Period:
   • If you haven’t set a start date yet, the text at the top will prompt:
     “When did you start your period? Select a day in the calendar.”
   • Click or tap on the day in the calendar that you want to mark as your period’s first day.
   • A small popup will appear, and you can press “Set as Start of Period” to confirm. This date becomes the anchor for calculating menstruation days, ovulation estimates, and pregnancy-chance percentages.
4. Interpret the Calendar:
   • Red cells indicate menstruation days.
   • Pink cells are near your ovulation day.
   • Other cells are classified as pre-ovulation or post-ovulation.
5. Review Pregnancy Chances:
   • Each date in the calendar will show a small percentage (e.g., “15%”) at the bottom.
   • This percentage is an estimate of how likely pregnancy could occur if unprotected intercourse happens on that day—based on your selected start date, cycle length, and known fertility day patterns.
6. Restart or Adjust:
   • If you want to change or reset everything, press the “Restart” button to clear your period start date and recalculate.
   • You can also update your Cycle Length at any time to see how it shifts the calendar.

Important Note:
This tool provides only an approximation of menstrual phases and fertility windows based on average biological patterns. It is not intended as medical advice. Always consult a healthcare professional for precise guidance regarding fertility, pregnancy, and reproductive health.