How Many Weeks Am I? Find Out How Far Along You Are

So, you’ve just found out that you’re pregnant!

One of the first things you’re probably wondering is: how many weeks am I?!

It’s important to understand that when yourself, a doctor or midwife calculates the estimated due date, it’s using a simple formula based on averages. So that magic, exciting date wont be totally accurate.

A a full term pregnancy is 37 to 42 completed weeks of pregnancy.

As little as 3-5% of babies are born on the due date, with roughly 40% born in the two weeks prior, and the same amount in the 2 weeks after.

Once you’ve worked out the date, you might like to announce that your baby is due around the 4th of October or sometime in October, so friends and family don’t jump all over you and hound you all day on the 4th of October! It might sound fun now, but ask anyone who is about to have a baby, and they’ll wish no-one knew their secret!

The estimated due date (or as I like to call it the ‘guess date’) is right in the middle of those weeks – 40 weeks. So if you prepare for the likelihood of 42 weeks of pregnancy, you’ll experience less disappointment if your estimated date comes and goes. First pregnancies tend to last longer than subsequent too.

Many factors come into play, so you can never be completely accurate as to a baby’s due date! A study was even published where they recorded guesses from doctors, midwives and mothers – and no-one was more accurate than the other!

How Many Weeks Am I?

Week 1 of your pregnancy starts on the first day of your last period. Weird huh?!

But it provides an exact date doctors and midwives can go by for the sake of specifics.

Unless you’ve had assisted conception and know exactly when the egg was fertilised, the exact moment of ovulation and conception is usually unknown.

The reason why due dates are notoriously inaccurate is due to how due dates are calculated. It’s assumed you have a 28 day menstrual cycle with ovulation on day 14. As you likely know, every woman has a unique cycle length and ovulation day. You may have a shorter or longer cycle than 28 days and you may have ovulated any time in between!

But for the sake of a date, everyone’s pregnancy is calculated based on an average. Therefore when you miss your first period, you’re already 4 weeks pregnant.

Okay, got it, but how many weeks am I, you ask…

To find out how many weeks you are, use our pregnancy calculator. It will give you an estimated due date and estimated date of conception. It will also tell you how many weeks pregnant you are, and how long you have to go until you reach the end of full term pregnancy at 42 weeks.

What If I Don’t Know When My Last Period Was?

If you don’t remember when your last period arrived or if you’ve not had a period for a while, you can book an early pregnancy ultrasound to try and work out how many weeks pregnant you are. Calculations based on your own, unique cycle is most accurate, followed by early ultrasound, then late ultrasound. The reason for this is when a baby first forms, they follow some pretty uniform growth pattern as they develop all the necessary building blocks. But as they get bigger, they develop at their own rate – genetics come into play.

Its best to avoid ultrasounds where you can, especially early ultrasounds which are often internal. This means the ultrasound is placed very close to your developing baby. Have an ultrasound if you must, but try to keep the time to a minimum and avoid any that are unnecessary.

What Happens During Each Week Of Pregnancy?

Don’t forget to visit our pregnancy week by week section, which contains information about changes in your body and your baby, week by week. Each week also has an image of what your baby and belly might look like!

All the best for a wonderful pregnancy – and be sure to bookmark BellyBelly for all your pregnancy questions and answers. Join our Facebook page for updates on all the latest articles.

Last Updated: August 31, 2015


Kelly Winder is the creator of, a doula, writer and mother to three awesome children. Currently, she's travelling the world for 12 months with her partner and children, and hopes to inspire more families to do the same. Visit for more information.


  1. I had sex 29 Aug 2015, my last period was 22 Aug 2015, Im not sure when my day of ovulation iss, so is it posible that i may be pregnant ?? Please help me … ThnQ

  2. I wanted to know how far I am along that i am in my pregnancy my last menstrual cycle was 9/26/2015-9/30/2015 after that I had got the nexplanon birth control 10/16/2015. And found out I was pregnant 11/11/2015 so my doctors dont know i far i am i need help

Leave a Reply

Your email address will not be published. Required fields are marked *