Tool
Estimate your ovulation day, fertile window, and safe period with a color-coded cycle calendar.
The most common method is the "calendar method": ovulation typically occurs 14 days before your next period. Subtract 14 from your average cycle length to estimate which day of your cycle ovulation occurs. The fertile window spans roughly 3 days before to 2 days after ovulation, since sperm can survive 3-5 days and an egg remains viable for 12-24 hours after release.
The calendar method is only an estimate and should not be relied upon as the sole method of contraception. Menstrual cycles can vary due to stress, illness, lifestyle changes, and other factors. For reliable birth control, consult your healthcare provider about options that suit you.
This calculator is for reference only and does not constitute medical or contraceptive advice. Results are based on averages and actual ovulation timing varies between individuals. For family planning or contraception needs, please consult a medical professional.