Whether you're already pregnant and want to know when it happened or are trying to get pregnant and want to know when best to actually get pregnant, knowing how to calculate conception date is very important.

Those using natural birth control use this date to avoid becoming pregnant.  This is the date when you are most likely to get pregnant.  Depending on the length of your cycles, it could be easy or complicated to calculate.

For those who have regular cycles, the date you are most likely to become pregnant is relatively easy to calculate. Your pregnancy conception calculator: if you have 28 day cycles and your period comes on a Sunday, you take the calendar and march it out to the fourteenth day, also a Sunday.  This is the day you are most likely to become pregnant.  Because sperm last for up to two days in the birth canal, you could get pregnant up to two days before the allotted date.

Also, because the egg, released on the fourteenth day, lives up to 24 hours after being released, you can reasonably expect to get pregnant up to the next day after the egg is released.  This gives you days 12-15 as possible conception days with the real date of conception being sometime on the fourteenth day.

If you have irregular cycles, the day of conception becomes a bit more complicated.  If you have regular cycles but they are longer than the regular 28 day cycle, keep a calendar to determine how long your cycles actually are. For example, if they are 35 days in length on average, you have 35 day cycles.  Remember that day 1 is the first day of regular flow in your menstrual period and you count forward from there.

In a thirty five day cycle, your best day for conception is exactly 14 days before you expect to get your period again.  For it is the last half of the cycle, the luteal phase, that is exactly fourteen days in everyone; it is the proliferative phase, or the first half of the cycle, that varies from person to person.  Again, it is the two days before the time of ovulation, or release of the egg, and the one day after ovulation that you are most likely to become pregnant.

But what about the situation where you have completely irregular cycles?  If those cycles are abnormally shorter than 28 days, you may not be ovulating at all and you will need to see your doctor about options for jump starting ovulation and creating longer cycles.  If you have irregular cycles that are longer than 28 days, you may just be one who ovulates irregularly, making it difficult to determine the exact day of ovulation.  Calculating by calendar may be impossible.

Here is your conception calculator: in such situations, it may be a good idea to purchase an ovulation test kit, one with a nine-day sampling.  Such kits involve urinating and determining the amount of luteinizing hormone and follicle stimulating hormone in the urine.  When the test strip turns the specified color, ovulation has occurred and that is your date of ovulation.  You have twenty four hours to conceive a child after the test has turned color.  It is more complicated, but is sometimes the best way to know when you are likely to conceive.

You may also have heard of the Chinese conception chart which is particularly important for them as they use it for a conceive boy calendar.