How to tell when you ovulate

Last updated: 2019-09-16  |  872 Views  | 

How to tell when you ovulate

When do I ovulate?
There's no foolproof method to predict when you'll ovulate, or release an egg from one of your ovaries. But here are a few ways you can estimate when it's most likely to happen, so you can try to time sex or intrauterine insemination (IUI) accordingly and boost your chances of getting pregnant.

(If that egg gets fertilized by a sperm and implants in your uterus, you're pregnant!)

Try the calendar method
If your cycle is regular – the same number of days each time – you can try the calendar method (also known as the Standard Days Method).

To estimate when you'll ovulate, count back 14 days from when you expect your next period. Your fertile window includes the day you ovulate and the preceding five days. So, for example, if day 1 is the first day of your period and day 28 is the day before you expect your next period, you'd be fertile on days 10 through 15. (But you're much more likely to get pregnant during the final three days of this window.)

This method is the easiest way to estimate your fertile window, but it's not very accurate, even if you have a good idea of when your next period will start. That's because ovulation rarely happens exactly 14 days before menstruation.

In one large study of women with 28-day cycles, the day of ovulation varied from seven to 19 days before menstruation. Ovulation happened 14 days before a period only 10 percent of the time.

So you can see how it's possible to miss your fertile window altogether using this method. On the other hand, it's easy and free and worth a try, especially if you're not in a hurry to conceive.

You can use BabyCenter's Ovulation Calculator to find out which days you're likely to be fertile according to the calendar method and what your due date will be if you conceive.

Use an ovulation predictor kit
Testing your hormone levels with an ovulation predictor kit (OPK) is a more dependable way to identify your fertile window, though it doesn't work perfectly for all women.

There are two kinds of kits: The most common type tests your urine, and the other tests your saliva. Both show a positive result in the days before you ovulate, giving you time to plan ahead for baby-making sex.

The pee-on-a-stick test indicates when your level of luteinizing hormone (LH) has gone up, which usually means one of your ovaries will soon release an egg. With the saliva test, you use a microscope to spot a pattern in your dried saliva that indicates the rise in estrogen which happens in the days before ovulation.

The kits are available at drugstores without a prescription. But they can be costly at $20 to $50 each.

Learn more about ovulation predictor kits.

Chart your cycle
You can also track subtle changes in your basal body temperature (BBT), cervical mucus, and cervical firmness for a few cycles to try to determine when you ovulate.

If you pay attention to these clues and note them on a chart or app, you may see a pattern that can help you predict when you're likely to ovulate next. (If your periods are irregular, you may not notice a pattern.)

Your BBT is your lowest body temperature in a 24-hour period. You use a special thermometer to measure it every day, right when you wake up. After ovulation, your BBT will rise 0.5 to 1.0 degree Fahrenheit and stay that way until you get your period.


Cervical mucus is the vaginal discharge you sometimes find in your underwear. During the few days before your ovulate and immediately after ovulation, you may notice an increase in cervical mucus and a change in its texture. It'll be clear, slippery, and stretchy, like raw egg whites.

When you're ovulating, your cervix is softer, higher, wetter, and more open. You can feel these changes if you reach inside your vagina with a finger. Charting is free (after you buy the thermometer), but this method takes time and effort to do accurately.

Learn more about how keeping track of your BBT and ovulation symptoms can help you predict ovulation. Then follow the steps to charting your BBT and cervical symptoms.

Be aware of other ovulation symptoms
Some women report certain symptoms during ovulation, such as spotting or cramping. Although this isn't a precise way to determine when you're ovulating, it may be helpful to be aware of these symptoms (if you have them) while using the calendar, OPK, or charting methods.

Learn more about the signs and symptoms of ovulation.

The following experts contributed to this article:

Nathaniel DeNicola, M.D., ob-gyn at the Center for Digital Health and The George Washington University Hospital

Allen J Wilcox, M.D., Ph.D., senior investigator, Reproductive Epidemiology Group, National Institute of Environmental Health Sciences

Powered by