This conception calendar helps all pregnant women determine when they’ve conceived their baby or when are the best times to do so in the following 12 months. Below the form you can find more information on the menstrual cycle, conception and estimated pregnancy dates.

The first day of your last menstrual period: *
Menstrual cycle length: *
Please choose whether you prefer to enter the birth date (due date):
Birth Date (due date): *
or the data of the menstrual cycle:
The first day of your last menstrual period: *
Menstrual cycle length: *

How does the conception calendar work?

This useful tool can determine 3 types of information from various perspectives as just a few clicks away. There are two tabs from which you can choose to you keep track of your menstrual cycle and important dates such as the ovulation date for the following 12 months together with the pregnancy due date or it can find the conception date.

By the 1st tab the conception calendar uses your first day of your last menstrual cycle and the menstrual cycle length in order to display an analysis of the following menstrual cycles in terms of fertile days when you can conceive, with a particular interest on the ovulation date and on the estimated pregnancy due date in case of a pregnancy.

By the 2nd tab you can get the estimated conception date.

Example of conception prediction:

■ First tab: Example calculation for a cycle of 28 days started on November  10th 2014: (the first 5 months depicted)

Ovulation date Most fertile days Estimated due date
Nov 24, 2014 Nov 22 - Nov 26, 2014 Aug 17, 2015
Dec 22, 2014 Dec 20 - Dec 24, 2014 Sep 14, 2015
Jan 19, 2015 Jan 17 - Jan 21, 2015 Oct 12, 2015
Feb 16, 2015 Feb 14 - Feb 18, 2015 Nov 09, 2015
Mar 16, 2015 Mar 14 - Mar 18, 2015 Dec 07, 2015

■ Second tab: For instance, someone born on March 15 1986 is likely to have been conceived around June 22nd 1985.

Or a pregnant woman with a cycle length of 29 days and first day of last period April 30 2014 is likely to have conceived May 12th 2014.

What is conception?

Conception is also known as fertilization or fecundation and represents the moment of fusion between the male sperm and female egg. This process leads to the development of an embryo that during the pregnancy, after 38 weeks time will develop into a new born ready to be birth.

Conception usually occurs during the 5-7 fertile days at the middle of the menstrual cycle with the highest chance to conceive, during the ovulation day.

The date of conception depends on the female body menstrual cycle dates as the fusion between the egg and sperm can only take place when the egg is matured and released from the ovary and this only happens during ovulation.


1) Wilcox AJ, Baird DD, Weinberg CR (1999) Time of implantation of the Conceptus and loss of pregnancy. New England Journal of Medicine 340 (23): 1796–1799

2) Beckmann CRB. (2010) Obstetrics and Gynecology. Lippincott Williams & Wilkins. pp. 306–307

14 Dec, 2014