Calculate your ovulation to identify your fertile window

If you’re trying to conceive, timing is key. Finding your fertile window -- the five day period of time leading up to and including ovulation, plus the day after (so, six days total) — is essential. Predicting your fertile window may increase your chances of getting pregnant by telling you the best time to have sex based on peak fertility. Sometimes the fertile window can feel elusive, but hopefully estimating your ovulation will help you understand and track your unique cycle.

Ovulation Calculator

The first day of your last period:

Average cycle length(days):

Results

Your estimated ovulation date range

Your estimated fertile window

The first day of your last period

Average cycle length (days)

The biological fertile window is defined as the day of ovulation and up to five days beforehand (and two days after!). Sperm can survive approximately 3-5 days inside the body, and an egg can survive up to 24 hours inside the fallopian tube following ovulation. Per the American College of Obstetricians and Gynecologists (ACOG), your chances of becoming pregnant are the highest if live sperm are present in the fallopian tubes when ovulation occurs. ACOG also suggests having sex once a day or every two days during your fertile window if you are trying to conceive.

This calculator estimates your fertile window and is not a guarantee of ovulation, pregnancy, or of birth control. The information obtained from this calculator is not medical advice, and should not be used as a substitute for guidance from or evaluation by a licensed healthcare provider.

Ovulation Calculator: Fertility Calendar Predictor

How Your Ovulation Dates are Calculated

Our ovulation calculator uses the projected start date of your next period to pinpoint your fertile window—the days surrounding ovulation when one is most likely to become pregnant. While this form of fertility calendar is fairly predictable, every person’s body is unique. Please keep in mind that ovulation tracker results are estimates, and should not be used as a means of birth control, or as a substitute for guidance from a licensed healthcare provider.

The National Institutes of Health (NIH) defines a regular menstrual cycle as being from 21 days to 35 days in length, with an average length of 28 days, and ovulation occurring approximately 14 days prior to the beginning of the next cycle. This calculator uses the fact that the luteal phase (which occurs after ovulation) generally remains consistent at 14 days, along with your given cycle length and beginning date of your most recent cycle, to estimate ovulation.

Signs and Symptoms of Ovulation 1

A higher-than-usual basal body temperature
Discharge that resembles uncooked egg whites
Physical changes to the cervix such as a softer, more open position and/or more moisture
Physical symptoms like spotting, abdominal bloating and/or cramping, and tenderness of the breasts
More subjective symptoms, like changes to your sex drive, mood, appetite, or even sense of smell

Tips for Getting Pregnant

Create Optimal Conditions 2

Maintaining a high standard of holistic health is one of the best ways to increase your chances of getting and staying pregnant. Not to mention, having good health throughout pregnancy tends to yield positive outcomes for both you and your baby.

Make a Plan With Your Partner

Coordinate intimacy with your partner to take advantage of your fertile window (which you can calculate using our ovulation predictor) while making sure that each of you feels good about the process moving forward. Honest, compassionate communication is key.

Pay Attention to Your Body

Use tools like this ovulation calculator and your own tracking methods (such as a journal of physical symptoms) to uncover personal physical signs of ovulation.

FAQs About Ovulation

What is ovulation?

Ovulation is the process through which the human body releases an egg from the ovaries, putting it in a position to potentially be fertilized by a sperm and result in pregnancy.3

How many days after a period is ovulation?

In a study, ovulation occurred typically over a 10-day spread, when considering a 28 day cycle, with the most common day of ovulating being day 15.4 You can also measure out your approximate ovulation period by counting backward 14 days from the projected start date of your next period.5

How long does ovulation last?

Once released from the ovaries, a human egg is typically viable for 12-48 hours.6 The total fertility window surrounding ovulation lasts between five and six days, depending on the individual’s cycle.7

How long can sperm live inside you to get pregnant?

Sperm can survive and remain viable for fertilization inside the reproductive tract for up to five days.8 In fact, sperm that’s already present in the fallopian tubes at the time of ovulation is most likely to successfully fertilize an egg.9

What are the odds of getting pregnant during ovulation?

An individual’s exact odds of getting pregnant during ovulation depend upon a number of unique factors, but typically, one has the best odds of pregnancy during the two days leading up to ovulation,10 ovulation day, and the two days after ovulation.11