Conception Calculator

Estimates conception date in case of an ongoing pregnancy or based on a date of birth.

Birth Date (due date):
The first day of your last menstrual period:
Menstrual cycle length:

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Steps on how to print your input & results:

1. Fill in the calculator/tool with your values and/or your answer choices and press Calculate.

2. Then you can click on the Print button to open a PDF in a separate window with the inputs and results. You can further save the PDF or print it.

Please note that once you have closed the PDF you need to click on the Calculate button before you try opening it again, otherwise the input and/or results may not appear in the pdf.

The conception date is when a sexual intercourse takes place and it is situated at a range of a few days before and after the ovulation date.

The conception calculator determines the probable conception date in two different cases:

■ Based on a known date of birth;

■ For an ongoing pregnancy: where the date of the last menstrual cycle and average menstrual cycle length are known.

The first method can be used for entertainment purposes, for those wondering when themselves or their baby has been conceived.

The second method can be used by expectant mothers, interested to know on what date of their menstrual cycle their baby was conceived.


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

Marieb EN, Hoehn K. (2013) Human Anatomy and Physiology, 5th ed. Pearson

Specialty: Obstetrics Gynecology

System: Reproductive