Tracking Your Fertile Window With an Ovulation Calculator

When do I ovulate?

If you ask yourself this question — whether you’re trying to conceive or looking to prevent pregnancy — using an ovulation calculator or an ovulation calendar might work for you.

An ovulation calendar or schedule is a tool used to calculate your most fertile days and track your menstrual cycle. This can help take some of the guesswork out of trying to get pregnant.

Some people turn to an ovulation calendar because they may have symptoms or medical conditions that prevent them from using birth control. Others may not like using birth control for personal reasons.

Ob/Gyn Erin Higgins, MD, explains what an ovulation calendar is and how it works.

What is an ovulation schedule?

Used to follow your menstrual cycle, a fertility calendar or ovulation tracker can help you calculate your most fertile days.

The average length of a menstrual cycle is 28 days. Ovulation, which is when your ovary releases an egg, happens around 14 days before bleeding begins. Your best fertile window — the greatest chances to get pregnant — is five days before ovulation and the day of ovulation. You’re less likely to become pregnant the days before and during your period.

During ovulation, the egg travels down the fallopian tube where it can be fertilized if there is sperm present. If so, the egg and sperm will create an embryo.

Signs of ovulation

So, how do you know if you’re ovulating? The most common symptoms include:

• Tender breasts
• Bloating
• Minor pelvic or abdominal pain
• Light bleeding or spotting
• Changes in the position and firmness of your cervix
• Increased sex drive
• Heightened sense of smell, taste or sight
• Mood changes
• Appetite changes

Ovulation tracking

You can use an ovulation date calendar — whether you use an online version, an app or keep track on your own — to figure out your most fertile days.

Remember that your menstrual cycle doesn’t just include the days when you experience bleeding.

“When we’re talking about a menstrual cycle, we’re talking about the entire month,” explains Dr. Higgins. “You’re only bleeding for a few days.”

Your menstrual cycle begins the first day of bleeding and ends the next day before your period.

How to calculate ovulation

To figure out your ovulation schedule, you need to work out the average length of your menstrual cycle.

To do so, track your next three menstrual cycles. Start with the first day you have bleeding (the start of your period) and count the days in between the start of your next period. After the three months, add those three numbers together and divide by 3. That will be your average length of a menstrual cycle.

For example, if your first cycle was 27 days, your second was 30 and your third one was 28, your average would be 28 days.

The next step is to pinpoint your most fertile days. Ovulation happens about 14 days before your period starts. For example, if your average menstrual cycle is 28 days, you should ovulate on day 14, making your most fertile opportunities days nine to 14.

How to use it for pregnancy planning

Using an ovulation calculator can be a great tool for people who aren’t on birth control. Depending on whether you want to conceive or avoid a pregnancy, it can help you figure out the best time to have sex.

Other methods can also help you determine if you’re ovulating:

• Check your basal body temperature. Ovulation can cause a slight increase in your basal body temperature. Use a thermometer that displays decimal points to take your body’s temperature at the same time each day. You want to look for your temperature to increase between 0.4- and 1 degree Fahrenheit.
• Examine your cervical mucus. During your menstrual cycle, your cervical mucus or vaginal discharge changes in color, texture and amount. You can use your fingers or a cotton swab to collect and observe your mucus. If it looks like raw egg whites, you might be ovulating.
• Use an ovulation prediction kit. Like a pregnancy test, you’ll need to pee on a stick. The results will show if you have an increase in hormones, meaning you’re ovulating.

Using these methods or an ovulation schedule for getting pregnant can narrow down the window of opportunity.

“A lot of people want that very specific detail so they can have timed intercourse,” says Dr. Higgins.

Can you calculate if you have irregular cycles?

If your period is irregular or you go months without a period, you may not be ovulating every month, notes Dr. Higgins. It can be tricky to calculate the best time for ovulation, especially if your period isn’t regular.

In this case, it’s best to talk to your healthcare provider so they can rule out any serious conditions, like PCOS, thyroid conditions or hormonal imbalances.

“Tracking your cycles can help determine just how irregular your cycles are. Sometimes, patients feel like their cycles are totally unpredictable, but when we take a step back, they really only vary by a couple of days,” explains Dr. Higgins.

“On the other hand, if your cycles truly are irregular, this information will greatly help your healthcare provider to figure out next steps.”

Bottom line?

Having as much information as possible when it comes to your ovulation can help reduce stress, whether you’re hoping to start or grow a family now or sometime later — or even if you don’t envision children in your future.

“Ovulation tracking is a cheap and easy way to monitor your cycles,” concludes Dr. Higgins. “It allows you to time for (or to avoid) intercourse.”