A woman is able to become pregnant (fertile) only during a certain part of her monthly
cycle. That is just before and during ovulation. By learning when you ovulate, you
can predict when you’re likely to be fertile. This calculator gives approximate ovulation
dates and fertile times for women who have regular periods. (Regular periods mean
having a period every 21 to 35 days.) Fertility charting, basal temperature tracking,
and purchased ovulation test kits can also be used to help predict a woman’s fertile
times. These are especially useful if a woman has irregular periods.
Please note that the date you enter in the calculator may result in an ovulation date
that has already passed. This will occur if you are nearing your next menstrual start
This calculator is not meant for women who are already pregnant. It cannot and should
not be used as an aid to preventing pregnancy. This calculator is provided for educational
purposes only. It is not intended as a substitute for professional health care. Always
consult with a healthcare provider for advice concerning your health.
Given the information you provided, your next ovulation date is estimated to be .
You are likely to be most fertile on the day of ovulation and during the 4 or 5 days
just before ovulation. Studies have shown that to increase your chances of getting
pregnant, you should have sex once a day or every 2 days during your fertile days.
Sperm can live for a few days and the egg can live about a day. Most experts suggest
you try every other day or every day starting about 5 or 6 days before you expect
to ovulate. Continue up through the day of ovulation or the next day.
How is my estimated date of ovulation calculated?
On average, a woman with a regular 28-day cycle ovulates on about the 14th day of
each cycle. If a woman’s cycle is longer or shorter than 28 days, the predicted ovulation
date is changed accordingly. For example, during a 24-day cycle (4 days shorter than
the average), ovulation takes place on about the 10th day. Similarly, changes are
made in the opposite direction for cycles longer than 28 days. Stress, illness, and
other things can also affect the timing of ovulation. Irregular cycles or cycles that
are shorter than 21 days or longer than 35 make calendar prediction of ovulation unreliable.