Chances of getting pregnant by day calculator

Timing is everything

If you’re trying to fall pregnant, the timing of when you and your partner have sex is critical. Our new online calculator will help you understand your Fertile Window - so you know the best time to have sex to give you the highest chance of conceiving.

When am I most fertile?

The most fertile time in your cycle are the days leading up to ovulation, before the egg is released from the ovary.  After ovulation the egg survives for just 24 hours, while sperm retain fertilising capability for two to three days in the fallopian tubes.   For this reason, we recommend that couples have sexual intercourse every two days throughout the females Fertile Window.  This means that sperm are ready and waiting for the egg when the female ovulates.  If you wait until after the female has ovulated before you have sex, you will most likely have missed the opportunity for conception that month.

When does conception take place?

Conception starts at the moment of fertilisation, when the sperm penetrates the outer shell of the egg, and an embryo is formed. Over the next four to six days the embryo moves down the fallopian tube to the uterus, where it implants in the uterus lining and hopefully continues to grow. To check if you are pregnant, you should wait two weeks after ovulation before undertaking a pregnancy test.

Calculate Your Fertile Window

To calculate your Fertile Window, you need to determine what day you ovulate.To do this, you need to know the length of your menstrual cycle (which tends to vary from 23 to 35 days). To calculate this – you should note how many days have passed from the first day of bleeding in your last period, to the first day of bleeding in your next.From this figure, subtract 14 days from the end of your current cycle to determine the day you ovulate.If you have irregular menstrual cycles, or your cycle length varies from month to month, it will be difficult to calculate your ovulation date. Ovulation urine tests may be useful, and you should consider seeking further advice from your GP or a Fertility Specialist.

How long should I try for, before seeking specialist advice?

Conception is a complicated sequence of events because all of the following need to be in place for it to occur:

  • Regular egg production by the ovaries (ovulation)
  • Healthy sperm, with the ability to move (motility) and the correct shape (morphology)
  • Unblocked and healthy fallopian tubes and uterus

The number one factor affecting a couple’s chances of conceiving is the woman’s age. The number of healthy eggs a woman’s ovaries contain will dramatically decline with age; and especially for women over 35. Most people start to consider seeking professional advice after six months of trying to conceive naturally without success. This is even more important if you’re over 35.

Want to know more?

If you’re keen to know more about the menstrual cycle, read about female reproduction….

If you’d like to consult with a Fertility Specialist about irregular periods and ovulation, or difficulties conceiving naturally, then please contact us.

Identify when you are most fertile

Women who know when they ovulate and when they are most fertile have a higher chance of getting pregnant during that cycle. Most other sites incorrectly calculate your fertile days and ovulation. babyMed has the most accurate ovulation calculator to determine your fertile window. It can also be used for early pregnancy detection.

Chances of getting pregnant by day calculator

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Improve your chances of getting pregnant

If you want to improve your chances of getting pregnant, you need to answer one simple question: "When do I ovulate and when are my fertile days?" Knowing exactly if and when you ovulate is the single most important information you need to know when trying to get pregnant (in addition to knowing that your partner has a healthy sperm count). You can only get pregnant from having sex on your fertile days, which are the 4-5 days before and the day of ovulation. If you know when you ovulate, you can also time sex better.

What causes ovulation to occur?

When your body is close to ovulation, LH levels start to rise. FSH, or follicle-stimulating hormone, causes the egg to quickly mature in preparation for the ovulatory phase when the egg is released from the ovary. The luteinizing hormone causes a gradual increase in estrogen. As you move from the follicular phase to the ovulatory phase, LH rebuilds the lining of the uterus. The uterine lining thickens and fills with blood and nutrients in preparation for egg implantation. This process occurs every month until an egg is implanted in the uterine lining or your period begins. Increased estrogen thins cervical mucus to help sperm travel toward the egg. Estrogen levels continue to gradually rise until they hit the tipping point that triggers an LH surge. LH surge is a drastic increase in estrogen that forces the follicle to release the mature egg. When the egg releases into the fallopian tube it is known as ovulation.

How accurate is this ovulation calculator?

This is the most accurate babyMed proprietary formula and was developed by an Ob-Gyn (who has over 30 years experience and has delivered 5,000+ babies) to help you calculate your fertile days to improve your chances of getting pregnant. The babyMed ovulation and fertility calculator will calculate your most fertile days to have sex, and it will also help you predict the precise day you will ovulate. It will also calculate the implantation day, when to expect the first pregnancy signs and symptoms, and when your pregnancy test could become positive. In addition, it will tell you the days you are less fertile, and less likely to get pregnant.

How do I use the ovulation and fertility calculator and calendar?

First, enter the first day of your last menstrual period. Then enter the average length of your menstrual cycles (average is usually around 28-29 days). If you don't know the exact length of your menstrual cycle or luteal phase, you can leave these at their default values (menstrual cycle: 28 days, luteal phase: 14 days). Try to record your cycle lengths if possible because that will help you to more accurately predict your likely date of ovulation.

What is the difference between the fertility window versus your fertile days?

The "fertility window" or "fertile window" consists of the 5-6 days during the menstrual cycle during which intercourse is most likely to result in pregnancy. You can get pregnant during these days, and your chances of getting pregnant increase the closer you have sex to the day of ovulation.  This fertile window extends runs for 6 days starting at 5 days before ovulation until the day of ovulation. Your most fertile days are the 4-5 days before and the day of ovulation.

Recent data show that ovulation could happen on several days of your cycle, even with a regular period, and ovulation does not always happen on the exact same day each month. Your fertility window is always 6 days, but he range of your fertile days as compared to the fertile or fertility window is potentially longer because your fertile days include all days during your menstrual cycle when you have the ability to become pregnant and takes into consideration a more flexible time period for ovulation. The fertile days assume different days for ovulation than the one calculated.  The fertile days are longer than the fertility window because ovulation does not always happen on the same day in each menstrual cycle but within a range of days. By calculating and identifying additional fertile days, not just the fertility window, we can provide couples with more flexibility to plan intercourse and more opportunities to conceive.

Calculate your fertile days and your fertility window HERE.

Can I get pregnant if I am having sex after ovulation?

Having intercourse the day after established ovulation is unlikely to improve your chances of getting pregnant. The egg lives only for 12-24 hours and sperm must be around when ovulation happens to improve fertilization and pregnancy. Increasing amounts of estrogen in the cervical mucus and reproductive tract of a woman approaching ovulation generally allows the sperm to live for up to 6 days.

Does ovulation always happen on the exact day of calculated ovulation?

Studies have shown that even in women with regular cycles, ovulation can happen any time, so "timing" of intercourse has never been shown to improve your pregnancy chances. You are probably not improving your chances of getting pregnant if you wait with intercourse until the temperature goes up or the OPK has become positive. You may already have ovulated by that time, and sex after ovulation is unlikely to get you pregnant.

In addition, you may improve your chances if you have sex once a day (as long as his sperm are OK) during the fertile 4-5 days before, and the day of, ovulation. In those rare circumstances when the man does not have enough sperm (oligospermia), the old rule of once every other day still holds true. 

  • Sex every day: 37% chance of pregnancy
  • Sex every other day: 33%  chance of pregnancy
  • Sex once a week: 15%  chance of pregnancy

How can we improve our chances to have a girl or a boy?

In addition to calculating your fertile days, this calculator also helps you improve your chances of having a girl or a boy by choosing either girl or boy or by default girl/boy in the drop-down menu. Following our recommendations could improve your chances of having one or the other, though it's not 100% sure.

For more tips to overcome fertility roadblocks and get pregnant faster, take our Fertility Course via email! 

Read More:
Due Date Calculator
Ovulation Calendar
Ten Tips to Get Pregnant Faster

Source: "Timing of Sexual Intercourse in Relation to Ovulation -- Effects on the Probability of Conception, Survival of the Pregnancy, and Sex of the Baby." Published in The New England Journal of Medicine (December 7, 1995 -- Vol. 333, No. 23). Allen J. Wilcox, Clarice R. Weinberg, Donna D. Bair

What day is your highest chance of getting pregnant?

You're most fertile at the time of ovulation (when an egg is released from your ovaries), which usually occurs 12 to 14 days before your next period starts. This is the time of the month when you're most likely to get pregnant.

What are the chances of getting pregnant on any given day?

The bottom line is that a single act of intercourse between a young couple has on average a one in 20 chance of pregnancy – this assumes the opportunity presented itself on a random day, as these things tend do when you are young.

How many days out of the month are you likely to get pregnant?

Most women have a 28-day menstrual cycle. That means you have about 6 days each month when you can get pregnant. That includes the day that one of your ovaries releases an egg, called ovulation, and the 5 days before. Having sex within that window is key.

How many days it will take time to get pregnant?

Conception (when the egg is fertilized by the sperm) can take place as soon as three minutes after sex or it may take up to five days. Implantation (when the fertilized egg attaches to the uterine wall) occurs five to 10 days after fertilization—which means it can happen anywhere from five to 15 days after you had sex.