A Simple And Proven Way To Know “How Many Months Is 20 Weeks”

how many months is 20 weeks

How many months is 20 weeks? The answer must be the oldest story in the book. For those who are looking for the final precise answer, it’s five months. And you are now halfway through your pregnancy. In the pregnancy length, 20 weeks is the midpoint of the whole distance.

If you go full term, the total pregnancy length has 40 weeks starting from your last period. So the short answer is easily proven. What about the long answer relating to time conversion from weeks to months? Let’s find out the full version of your question in this piece of writing.

Pregnancy length – Days, weeks, months, trimester

While many people are saying that pregnancy is nine months long, most of the ob-gyn references state that pregnancy is 40 weeks longs. The time is counted from the beginning of your last menstrual period.


A normal pregnancy counts 280 days from your last period. However, the first two weeks includes period time. As a result, the number of days from conception to birth remains about 266 days.

In fact, the conception date may vary from woman to woman. But the date of last menstrual periods is normally considered as the starting point of pregnancy. To put it simply, there is a consensus among ob-gyn experts that the pregnancy lasts for about 280 days, which is 40 weeks.


It is easy to refer from the 280 days of pregnancy that you have 40 weeks of gestation. Also, the maximum fetal age (conception to birth) is 38 weeks. So for example, you are in the 22nd week, this means that your fetal age is now at the 20th week.

One thing to note is, 22 weeks from the first day of your last menstrual period, you are “22 weeks pregnant”. And now you are entering in the week 23 of pregnancy. However, your baby is only 20 weeks old.


The counting of months is simple. The pregnancy month is counted as nine months on the calendar plus seven additional days of due date. Now you know that months range from 28 to 30 days. Thus, the average pregnancy lasts more than nine months a little bit.

For instance, if your last menstrual period is on January 1st, the due date is January 1st plus nine months plus seven days. Equally, the due date is October 8th. This calculation emphasizes that 40 weeks of pregnancy is exactly nine calendar months plus one additional week.


Trimesters are three periods of three months each. So the 1st, 2nd, and 3rd months make up the first trimester. The 4th, 5th, and 6th make up the second trimester. Similarly, the last three months make up the third trimester. Thus, 40 weeks of pregnancy equals to three trimesters plus one additional week.

However, what you should note is that health care providers normally count your pregnancy in weeks, rather than in trimesters or months. Trimester and month are usually used as time scales to note the critical stages of fetal development.

Specifically, in the first trimester, the embryo comes with its early development in structure. In the second one, the embryo, now a fetus, is in the form of recognizable human. And the final stage, the fetus becomes viable and can survive if born prematurely.

Converting from weeks to months, and from months to trimester

To wrap things up and make it easy, the standard pregnancy lasts for 9 ½ months, 40 weeks, and 280 days. And the fetal age is two weeks less than gestational age. This chart will further make the converting task easier to understand.

weeks month trimester

So how many moths is 20 weeks?

Just by looking at the table, you can know that if your pregnancy has lasted for 20 weeks now, you are in the 5th month. To be more exact, the gestational age is 4 ¾ months, and the fetus age is 4 ½ months.

For the rule of thumb, you can just divide the number of weeks by fours. The result will remain the same. How many months is 20 weeks? You now have the answer.

Nine months or ten months? Confusion debunked

The fact is, health care providers start their counting from the beginning of the last menstrual period. In other words, they start counting about two weeks before you even conceived. And as the pregnancy is 40 weeks, it is more than nine months. This means that as completed the nine months, you enter the 10th month and the baby can actually come at any day.


To put in a nutshell, even though preggers are eager to count their weeks and convert them into months, what more important is what week are you in. As long as you know how to count the days and week, there should be no problem in calculating the months. This piece of writing hopefully provides you with more than just the answer for “How many months is 20 weeks?”

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