Determining When Are You Most Fertile

The key to conceiving is getting the timing right. It’s important to figure out the span of days around when you ovulate. This is commonly called your ‘fertile window’. It refers to the days leading up to ovulation and the day of ovulation.

Ovulation is everything. This is when the egg in your ovary is released and moves down the fallopian tube. Once in the tube, it’s ready to be fertilized. Then you’re pregnant!

What are your most fertile days in the cycle?

Each woman has a similar time frame in which she has the best chances of getting pregnant. This comprises of the five days leading up to ovulation and the day of ovulation.

Because sperm can live several days in the uterus, having sex in the days approaching your ovulation allows your chances of conceiving to be greater. The sperm will swim around waiting for the egg to be released, then fertilize it.

An egg will only remain in your fallopian tube and uterus for 24 hours. It must be fertilized in that 24 hours. (Though, remember, that doesn’t mean you must have sex in that 24 hours.) After that, it has left your body, making it impossible for you to get pregnant until your next cycle.

It’s recommended that you have sex every two days to ensure you’re giving yourself the best chances of getting pregnant.

How to check or calculate when you’re most fertile

Every woman’s cycle can be different. Not only that but each of your own cycles can be different each month. Although we can give general guidelines on how to calculate when you’re most fertile, it won’t be exact until you implement these methods for yourself.

Basal body temperature charting

The best way that I’ve learned how to calculate when I’m fertile is using a Basal Body Thermometer and chart my temperature throughout the month. This is actual science and proves effective time and time again.

Each morning, I take my temperature before getting out of bed. This is called your Basal temperature or your resting temperature. Charting it every day will show you a pattern in your cycle. After you ovulate, your temperature will rise almost a full degree and remain high until you start your next cycle.

Using your temperature chart, you can accurately see when you ovulate and the days leading up to ovulation. This gives you an accurate window for your personal body and when it is most fertile.

Ovulation prediction kits

Many women rely on ovulation predictor kits to determine their most fertile ways. These work much similarly to pregnancy tests – ovulation predictor kits are affected by levels of hormones, thus giving a positive or a negative reading.

The ovulation predictor kit (OPK) registers the presence of the luteinizing hormone in the urine. It is important to keep in mind that the OPK will give a positive reading only during the ovulation day, making you miss the fertile days that come before the release of the egg from the ovary.

There are OPK strips and digital tests. The digital test is supposed to be more sensitive, thus providing a more accurate reading.

Calculating based on cycle length

Another way of calculating when you’re fertile period is, is simple mathematics and a general guideline based on your average length of a cycle.

Typically, ovulation happens 14 days before your next cycle begins. And remember that your fertile period is the day of ovulation and the 5 days leading up to it.

It’s important to track your cycle lengths for 6 months and take the average of the lengths. If you track the length of time between your periods for six months, this should give you a good indication of the length of your average cycle. Read on to find out when you are most fertile with different cycles.

When are you most fertile with a 24-day cycle?

This is a shorter cycle than the average woman, but you can still get pregnant with a 24-day cycle. This means you will typically ovulate on day 10.

So 10 days after you start your period, you will be ovulating. The 5 days leading up to ovulation day will be your fertile period. Therefore, days 5-10 of your cycle are the best times to try for a baby!

When are you most fertile with a 28-day cycle?

The average length of a cycle is 28 days. If you find yourself having cycles that last 28 days, you will most likely ovulate on day 14.

Your fertile period will be between day 9 and day 14, so those are the days which you have the best chances of conceiving.

When are you most fertile with a 29-day cycle?

With a 29 day cycle, your fertile window will begin 10 days after your period starts and it will end on the expected day of ovulation which is day 15.

With this cycle length, your fertile period is between 10 and 15 days after the beginning of your cycle.

When are you most fertile on the pill?

The pill completely stops ovulation. Even though you have a period every month on the pill, you aren’t releasing any eggs and therefore cannot become pregnant. As long as you’re taking it daily or however often you should be taking it, you will not be fertile while on the pill.

The only time you could get pregnant is if you just begin taking the pill. In some cases, the pill does not start taking effect until one week into taking them.

When are you most fertile after a D&C or a miscarriage?

Dilation and curettage is a procedure that removes built up tissue in your uterus. This is a typical procedure after a woman has a miscarriage or an abortion.

After a miscarriage doctors say you may have a small brief period where you can experience increased fertility. This doesn’t mean it will last for long and it might be best to avoid pregnancy as your body is sorting itself out.

It’s best to wait 4 weeks after your miscarriage to ensure your cycle returns to normal and your body is capable of conceiving again.

It’s also important that you take the time to grieve after a miscarriage or abortion. Losing your baby can be tough and it’s necessary for your emotional health to evaluate if you and your partner are ready for another attempt at conceiving.

When are you most fertile for a boy or girl?

There was a doctor in the 1960’s, Dr. Landrum Shettles who developed a method for figuring out how to conceive a boy or a girl.

After studying the movement and speed of sperm, he noticed that those carrying the X-chromosome (girls) traveled much slower than the Y-chromosome (boys). In addition, he noted that the girl sperm would live longer. This allowed a woman’s fertile period to last longer since girl sperm could survive longer in the uterus.

With this knowledge, if you’re trying to conceive a girl, you and your partner will want to have sex at the beginning of the fertile period in hopes that the girl sperm will survive the longest and be the ones that fertilize your egg.

On the other hand, if you’re trying for a boy, you will want to try conceiving as close to your ovulation date as possible. It’s a good idea to use OPK sticks to determine your exact ovulation date. That is the day you’ll want to have intercourse in attempts to get pregnant with a boy.

When are you most fertile for twins?

Though there is no specific time of a woman’s cycle that can increase her chances of having twins, there are a few factors that can increase the likelihood of twins.

The most common way to get pregnant with twins is using specific fertility treatments. Different fertility drugs will increase your chances of releasing more than one egg when you ovulate. When you release multiple eggs, there’s a chance that they will be fertilized and you’ll conceive twins or triplets.

If you go through in vitro fertilization treatment, your chances of giving birth to more than one child are 1-2 in 5.

Other natural factors also play into the chances of having twins. Things like age, heredity, race and the number of children you already have can increase your chances of having twins.


With a bit of learning, you can figure out how your body works and what cycle is normal for your body. With this information, you’ll be able to determine when you ovulate and how you can best know when to try to get pregnant.

Most importantly, enjoy this process as you learn about your body’s signals and signs. It’s exciting!