Ovulation Calculator – Know Your Most Fertile Days

Trying to get pregnant? Check out when you’re most fertile and when is it best time to get pregnant.

When you decide to conceive, you will find that despite the popular belief, it isn’t that easy to get pregnant. You don’t get pregnant right after the first few tries. The sperm needs to meet the egg and only then you can conceive, so you should know when you ovulate.

If you anticipate that and try to get pregnant when you are ovulating then you dramatically increase the chances of getting pregnant. Of course there’s no need to sit down with pencil, paper and calculator to figure this out. You can find multiple ovulation calculator on the internet that will help you find this out.


So here we explain the basics of what is ovulation calculator and other simple questions that you need to know on this topic.

What Is an Ovulation Calculator?

Calculating your ovulation will help you figure out your infertile days (your safe period when you can’t get pregnant), your fertile days (when you should try conceiving), and calculate when the pregnancy test is possible. You need to remember that these calculators are not 100% accurate. The sperm can survive for 3 to 5 days in the uterus while the egg can survive for about 12 to 18 hours. So you have a day of ovulation plus 5 days before it, resulting in 6 fertile days.

Don’t worry if you can’t get pregnant for several months of trying. The chances of getting pregnant, despite doing everything right, is 20%. It’s all about proper timing. You get pregnant if you try to conceive in this small window of time and the ovulation calculator helps you identify this window of opportunity.

So what you have to do is go to an online ovulation calculator, add the last date of your periods and the length of your menstrual cycle. This will help you figure out the fertile and infertile days. Also, these are just approximate days and not completely accurate.

When Do You Ovulate After Periods?

Assuming your menstrual cycle is of 28 days, with your first day of your period as the first day of the cycle, then you will usually ovulate sometime between day 10 and day 15 of your cycle. If your cycle is short then you will ovulate just some days after your period.

Do You Ovulate Every Month?

Surprisingly, no. Not all women ovulate every month. In case ovary is not producing mature follicle, there would be no ovulation. This is known as anovulatory menstrual cycle. In such cases, the lining of the uterus, develops as usual, but no egg is released.

Calculate 14 days before your next period, that’s when you will ovulate approximately, so you should have sexual intercourse 3 days before you expect to ovulate and 1 day after to increase your chances of pregnancy. If you have regular menstrual cycles, then you will ovulate each month.

A sperm transfers from vagina to the tube at a speed of 2 to 3 mm per minute. So after ejaculation, you may be pregnant just a couple of hours later. You should lie on your back after the sexual intercourse so that the gravity can help sperm in the process of going to the tube.

When Are You Most Fertile?

The most fertile window for a women trying to conceive is 12 to 16 days before periods. The ovulation calculator will help you figure out the ovulation date and you should try to conceive a few days before and a day after that ovulation day.

How To Calculate Fertile Days?

Fertile days are those days in your menstrual cycle when pregnancy is possible. First, you need to work out the length of your average menstrual cycle. Technically, pregnancy is only possible during the 5 days before ovulation and the day of ovulation. So these 6 days are your fertile days. They reflect the lifespan of the sperm, which is 5 days; and that of the ovum, which is 18 hours.

If you have intercourse on the 6th day before ovulation, then the chances of you getting pregnant are virtually nil. These chances increase to 10% if you try conceiving the very next day, i.e. 5 days before ovulation. The probability of getting pregnant rise steadily after that until the day of ovulation.

After you are done ovulating, your chances of getting pregnant if you try the next day drop again to zero. If you don’t want to keep track of the fertile and infertile days, then you should try conceiving every 2 to 3 days.

How To Calculate Ovulation Day?


You can easily figure out your ovulation day, even without using ovulation calculator. Figure out the average length of your menstrual cycle. You always start with that. First day of your period is the first day of your cycle and the day before your next period is your last day of the cycle. Ovulation occurs 2 weeks before your next expected period.

For example, if you got your period on the 1st July, and your average cycle is of 28 days, then you will probably ovulate around the 14th. Your most fertile days will be 12th, 13th and 14th. If your cycle is of 35 days then ovulation will happen on 21st. So the most fertile days for you will be 19th, 20th, and 21st. If you have a shorter cycle of 21 days then ovulation might happen on day 7 itself and your most fertile days would be 5th, 6th and 7th. In this case, having sex right after periods would lead to pregnancy.

What Are The “Safe Days” After Periods?

You can always find an online calculator for safe days. But for theoretical understanding, for calculating the safe period too, you need to work out your average period of your menstrual cycle.

So from the 1st day to the 7th day of your period, assuming your cycle lasts anywhere between 26 to 32 days, is considered infertile or “safe”. This may vary from women to women. World Health Organization (WHO) did a research study which reflects that approximately 80% of women have menstrual cycles that ranges from 26 to 32 days.

How Long Does It Take To Get Pregnant After Periods?

Assuming again that your menstrual cycle is of 28 days. So your period may end on day 5, and you ovulate around the 14th day. After the intercourse, it takes a few hours for the sperm to reach the egg, but then you are pregnant merely hours after the intercourse. Despite that, the pregnancy is considered to have started from day 1 of your last period, and you will know that you are pregnant after you miss your next period.

Can You Still Have A Period And Not Ovulate?

Some women can have an anovulatory cycle, which that ovulation has not occurred. During this time, you may shed a little which may seem like an early period but it is not a true period. So if you want to check whether you are really ovulating or not, check for other signs and symptoms like the cervical mucus or the basal body temperature. So yes, you can have a period and not ovulate. 

Can You Get Pregnant When You’re Not In Your Fertile Window?

Absolutely not. Getting pregnant is not as easy as people would make you think. It’s only in that short span of time, those fertile days, that you have a chance of getting pregnant. But if your cycles are irregular then your calculation about ovulation may get wrong sometimes so you can get pregnant. So check with your doctor about the fertile and infertile days for your cycle.

Ovulation Calculator: Boy

There is an online gender calculator rel=”nofollow” that predicts the gender of the baby. This is not 100% reliable. There is also a research study conducted by Dr. Shettles, that says that there are certain things that you can do to “favour” the conception of boys. This is also not 100% accurate. It just increases the chances of giving birth to a boy, it doesn’t guarantee it.


According to the study, the closer you are to ovulation when you have intercourse, the better are the chances. Other things that you can do to get a boy is – drink a glass of water with baking soda before intercourse as the alkaline environment favours boys (do not do this before reading the instructions by Shettles as it might be harmful if done incorrectly). Shettles recommends you to use the sex position of rear entry (doggy-style) and have orgasmic intercourse. Higher sperm count is important, so don’t have sex for a few days before that. It also helps if the man drinks a caffeinated beverage before sex.

Ovulation Calculator: Girl

According to Dr. Shettles in the same research study, if there are 3 days left till ovulation, then the sex is likely to result in conception of a girl. Also, drink a glass of water with vinegar to create an acidic environment that will favour a girl child (Read Shettles’ instructions before doing this).

Sex to have a girl should be in missionary-position with no orgasm for the woman. Have sex everyday so the sperm count is normal, and stop intercourse 3 days before ovulation. It would help your chances if your man took a warm or hot bath before intercourse.