Pregnancy Week Calculator: Mobile Application

Learn how to calculate the pregnancy date manually or automatically with a mobile application.

If you are pregnant and wonder when your baby will be born. Only about 3-5% of babies are born on the estimated probable date of delivery.

Dates based on your last menstrual period are more accurate, since ultrasound has a margin of error, even in the early stages, and is based on mathematical averages. That being said, you should carry your pregnancy calculator to get a rough idea of ​​when your baby will arrive.

It is considered normal when the average duration of your menstrual cycle is 28 days. The vast majority of babies know when it is time to be born according to their own physical preparation and development, so for this reason we recommend you remember that a pregnancy is still classified as a term until 42 weeks.

How to determine the date of delivery without knowing the day of conception?

The method usually used by health professionals is simply to count from the first day of your last menstrual period. For women with an average menstrual cycle, that day is usually about two weeks before conception, which explains why it is said that pregnancies last 40 weeks.

There are two ways to do it: 1) taking as the starting date the first day of your last menstrual period, and count 40 weeks from that date 2) if you know on the day of conception to count 38 weeks from there. From these two simple forms you can have an approximate of the probable date of delivery .

Of course, a calculation of the delivery date is always approximate. Only one in 20 women manage to hit the exact day.

Calculation through mobile application

In the digital age there are many applications for iPhone and Android  that facilitate these calculations and also monitor pregnancy.


In a healthy pregnancy, you are giving your baby the best chance of being born healthy and happy and, of course, with fewer complications for you as well. Routine and unnecessary inductions are only added to possible complications (including caesarean sections) and traumatic deliveries.