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Calculator of Conception

First day of your last menstrual period
Cycle Length
Second part of the cycle
Please, Enter all values correctly.

Online calculator of the date of conception. Do you want to know when your baby was conceived? The Conception Date Calculator calculates what date and your baby was conceived on based on the day of your last menstrual period and cycle length. The conception calculation is based on the average number of days per pregnancy.

The Pregnancy Conception Calculator estimates the date of conception based on the expected due date of the pregnancy, last period date, or ultrasound date. The date of conception is the day on which a person's baby is conceived. The calculator also estimates a possible range of days during which sexual intercourse might have led to conception based on sperm being viable for 3-5 days within a woman's body.

When Did I Conceive?

When exactly did I get pregnant? Many women ask this question when trying to figure out the exact day their pregnancy began. Often, gestational age, or the age of the baby, is calculated from the first day of the mother's last menstrual period. Biologically, the baby was not conceived until ovulation and the fertilization of the egg, which usually happens at least 10 days after the first day of the mother's last menstrual period.

Because there are many factors surrounding conception, it is difficult to pinpoint an exact date of conception. This calculator helps to estimate the date range of real conception and a possible range of days during which sexual intercourse might have led to conception. There are a few methods that can be used to estimate the conception dates.

Ways to calculate ovulation period

Try a conception date calculator which is very useful and accurate. These calculators are very easy to use as they require some basic information to perform the calculation of the conception period. These calculators are free to use and provide the answer in a few seconds.

Visit a doctor to know the ovulation period, which is the best and most accurate way to know the conception period. As they perform many exams to be sure of it along with many tests. Most of the women go for this option.

Another way is to try the new ovulation kits that are available in the online and offline market. Buying those kits can help you but those kits come with the doubt of accuracy.

Usually, women have a regular 28-day cycle such as if the last cycle began on 10th may then the next cycle should start on 8th June. But some women have irregular dates, which causes them trouble to remember numbers of the days in their cycle period. They can get help to know their conception date with the help of a conception calculator.

Chances of getting pregnant depend on many other things such as sperm count, sperm mortality. But the female body should be prepared to help the sperm hatching the egg.

Last Menstrual Period

Conception usually occurs around 11-21 days after the first day of the last period of a woman who has a regular period. The estimation of conception date is based on this, but is rarely ever exact since it is difficult to know exactly when ovulation occurs. Estimating conception date can also be more difficult for women who have irregular periods, or for those who don't remember the first day of their last period. In cases like these, one of the more accurate ways to estimate gestational age is through the use of an ultrasound.


During the first half of the menstrual period, the eggs in the ovaries start to grow. One of the ovaries starts to cause a surge in luteinizing hormone by secreting estradiol. This causes the release of a mature egg by rupturing the follicle. The egg connects the uterus with ovaries using fallopian tubes. The whole egg release process caused by the surge of LH is called ovulation. Ovulation generally occurs after 14 days on the first day of the menstrual period. But it varies for each woman.

Once the egg is released, it is very important to fertilize it in 12-24 hours or it will expire. When the cervical mucus is present a healthy sperm can stay 5 days in a woman’s womb. Conception calculator helps the ovulation date because the period is too short.

Due Date

An estimated due date, usually based on a sonogram, is typically obtained from a healthcare provider during a prenatal visit. Based on this due date, a range of possible conception dates can be calculated.


An ultrasound, on a basic level, uses sound waves to create images of internal body structures. An ultrasound used in the context of examining the progress of the fetus in pregnant women is referred to as an "obstetric ultrasound." This is done in real-time and is a fairly standard procedure that is part of prenatal care in many countries, as it can provide information about the health of the mother and embryo/fetus, as well as the overall progress and timing of the pregnancy. Ultrasounds can be used to measure a fetus as early as five or six weeks following the mother's last menstrual period. It is a more accurate measure in early pregnancy than it is in later stages. Ultrasound can be used in conjunction with estimates based on the last menstrual period to determine a more accurate gestational age.

How the date of conception calculator works

The time from conception to start labor takes time of approximately 39-40 weeks. To track the starting date of pregnancy, doctors count 266 days. Or a conception calculator can also help to know the estimated date of conception date. The estimated date is closest to the exact date as there is no way to know the exact date except if the mother had sex right after the menstrual cycle.

The conception calculator can also help to know the father in case of confusion. The mix of a breakup, divorce or other complications can confuse to identify the father. Using a conception calculator can help you to know the exact day of ovulation, the first day of the last menstrual period and possible dates of conception. But confirming who is the father of the baby with the DNA test is the best option. Conception calculator can provide the estimated dates of conception but it works by putting the due date, the first day of the last period and ultrasound.

Fertilization, Conception, and Pregnancy

Fertilization and conception are terms that are often used interchangeably. This calculator uses the medical and scientific definition of the terms. Fertilization occurs when the sperm and the egg combine in the fallopian tube, producing a fertilized egg, and beginning the process in which an embryo develops.

Conception refers to the process of becoming pregnant, which scientifically involves both fertilization as well as implantation into the wall of the uterus. On the state level (in the U.S.) there is some confusion between the use of the terms conception and fertilization due to differences in the definitions used. In some cases, a woman is considered pregnant after fertilization, but this is not in line with well-established scientific and medical definitions. The long-standing view of those in the medical profession, as well as federal policy (in the U.S.) considers a woman pregnant when a fertilized egg has implanted into the wall of her uterus. When this has occurred, the woman is said to have conceived. In other words, conception, medically and scientifically, requires both fertilization and implantation, and a woman is not considered pregnant until both have occurred.

Importend Notes and Disclaimer


Caveats and Recommendations: This calculator is NOT intended to diagnose illness or be used as a substitute for medical advice or treatment. Some models provide predictive outcomes which may not be accurate. Please consult a medical professional for any medical treatment or diagnosis advice.


Note: This calculator is presented for your own personal use and is to be used as a guide only. Medical and other decisions should NOT be based on the results of this calculator. Although this calculator has been tested, we cannot guarantee the accuracy of its calculations or results.


Disclaimer: This calculator is provided without warranty and CANNOT be used to diagnose or treat any disease or condition.

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