Ovulation Calculator

Up your chances of getting pregnant: This ovulation calculator will help you determine your “fertility window”

Please select the first day of your last menstrual period:
Usual number of days in your cycle:
28 Days

Also Use: Due Date Calculator, If you want to know when your precious is coming.

Also Use: Safe Days Calculator, If you want to have sex, but don’t wish to get pregnant.

  • Many couples who want to have children experience stress and pressure when trying to get pregnant. If you are not the ones to take your chances and wait for fate to get involved, you'll be pleased to know that you can up your chances if you learn to calculate your ovulation days. 

  • If you wish to conceive, you probably want to know when you have the most chance to conceive. Healthy couples who aren't using any kind of birth control methods have a 25 to 30 percent chance of conceiving during each monthly cycle. This percentage varies depending on the circumstances, of course. Mostly with age. 

What is an ovulation period?

  • It is critical to know that this percentage is actually pretty high, considering you can only get pregnant in your ovulation period. Ovulation time is a short period each month when the egg is viable to be fertilized. This lasts between 12 and 24 hours. On the other hand, sperm can live longer than the egg, from three to six days. Logically, this means that sperm basically hangs around for an egg to emerge before it goes down the fallopian tube. 

  • The menstrual cycle varies from 23 to 35 days, 28 being the average length. If you happen to have irregular menstrual cycles, calculating might be a little bit more complicated. I suggest taking your shortest period into consideration to be sure not to miss your ovulation date.

  • Making love to your significant other on the day you ovulate is, of course, an ideal scenario. After all, after that day, the window closes until the next cycle. If you wish to get pregnant, it would be great to learn to recognize ovulation signs. Good news; you can calculate the exact time in your monthly cycle you have the best chances to conceive. 

What is ovulation?

  • Ovulation is the process of releasing a viable egg from the ovaries. This process typically occurs somewhere around halfway through the menstrual cycle. Usually, this happens around day 13 of the average 28-day cycle, counting from the first day of one period to the next. 

  • Many women don't have an average monthly cycle, so there is a wide range of "normal" when it comes to the menstrual cycle. They can last from 23 to 35 days. The critical thing to know is that even your own cycle and ovulating time may vary slightly from month to month. 

  • To calculate your ovulation days, take the length of your menstrual cycle and subtract 14 days from the end of your current menstrual cycle to determine the approximate day of ovulation.

How long does ovulation last?

  • The specific time it takes for a fertile egg to be released by the ovary into the fallopian tube varies but typically occurs somewhere between 12 to 24 hours after being supported by a surge of hormone LH. 

  • Your body produces and distributes an increased amount of the hormone estrogen as you approach your ovulation period. This vital hormone is responsible for the lining of your uterus to thicken. It also helps create a sperm-friendly environment to increase your chances of you becoming a new mom. Increased estrogen levels cause a sudden increase in the hormone LH (luteinizing hormone) which causes the release of the matured egg from the ovary. And that's it. The ovulation typically occurs 24 to 36 hours post-LH surge. Hence why the sudden rise of this hormone serves as a solid sign of peak fertility. 

  • A viable egg is good to be fertilized for up to 24 hours after ovulation happens. If it doesn't stick, the lining of your womb sheds, and you get your period and start a new menstrual cycle. 

Also read: Can Female Masturbation lead to Infertility?

What is the difference between ovulation days and fertile days?

  • As previously mentioned, an egg can survive for up to 24 hours, while sperm can remain active for as much as five days. That means you can get pregnant if you have sex somewhere around four to five days before the egg release. So, the fertility window is about six days in which you can conceive. If you have unprotected sexual intercourse, of course. The chances of getting pregnant outside of this fertility window are pretty low. 

  • Knowing the exact days when you are most likely to get pregnant gives you more opportunities to plan sex with your partner. This flexibility will significantly reduce the pressure you might be feeling. 

Myths and misconceptions 

As with many things in life, myths and misconceptions are present in the fertility department. I will mention the most common ones, as well as the fundamental truths.

  • You cannot conceive the first time you have sex:

This is not true. The possibility of getting pregnant is always there if you have unprotected sex. If you don't wish to have a baby, choose a contraception method that suits you best. 

  • You can get pregnant on any day during the month:

This is also untrue. You can get pregnant if you have unprotected sex on the days leading up to and around your ovulation day. You should know that the day before, and the ovulation day, are your two most fertile days. Once your viable egg is gone, you cannot get pregnant until your next menstrual cycle. 

  • You can only conceive on the two days each cycle:

This is another common myth responsible for many surprising pregnancies. Actually, the "fertility window" lasts for up to six days. As already explained, sperm can live for up to five days, so having sex on the days approaching your ovulation day might increase your chances to conceive. 

Also read: Ovulation Symptoms: Ovulation signs & When Do You Ovulate?

Ovulation calculator is a great help

  • Calculating by yourself is okay, but nowadays, there are ovulation calculators available. Those really come in handy since menstrual periods are different from woman to woman and month to month. Our ovulation calculator will help you determine your most fertile days. You will also get an estimated window of days in your cycle you are most likely to get pregnant. 

  • It is an excellent tool that helped many couples reduce the pressure and anxiety when trying for a baby. And the less stress, the more chance you succeed in adding the sweet new member of your family.


University of Rochester Medical Center

National Institute of Health

National Institute of Health