How Many Weeks Pregnant Am I? How Far Along You Are

How Many Weeks Pregnant Am I? How Far Along You Are

You’ve just found out you’re pregnant… so, naturally, one of the first things you’ll be wondering is how many weeks pregnant am I?!

It’s important to understand that an estimated due date is calculated using a simple formula based on averages.

Not your own unique body, exactly when your baby was conceived.

So that magic, exciting date won’t be totally accurate, but it’ll be close.

How Many Weeks Pregnant Am I?

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

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

Once you’ve worked out the estimated due date, you might like to announce that your baby is due around the 4th of October, or sometime in October.


So your friends and family don’t jump all over you and hound you with calls, text messages, Facebook messages and emails 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 of their estimated due date!

Why The Estimated Due Date Is Really The ‘Guess Date!”

The estimated due date – or as I like to call it, the ‘guess date’ – is simply in the middle of the range of full term.

So if you prepare for the likelihood of 42 weeks of pregnancy (especially if you’re expecting your first baby, as they tend to take their sweet time), you’ll experience less disappointment and communication overload if your magic date comes and goes.

First pregnancies tend to last longer than subsequent pregnancies, but of course, not always.

Many factors come into play, so you can never be completely accurate as to a baby’s due date.

Even the experts don’t have an advantage when working out the date!

In a study on due dates, doctors, midwives and mothers had to guess what a baby’s day of birth would be.

The results?

No-one was more accurate than the other!

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So, How Many Weeks Pregnant 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.

With assisted conception, for example IVF, you might know exactly when the egg was fertilised.

But for other pregnant women, the exact moment of ovulation and conception is usually unknown.

Due dates are notoriously inaccurate, due to the way your 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!

Pregnancy due dates are calculated based on averages, so a date can be given.

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’ll give you an estimated due date, as well as an 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.

It’s best to avoid ultrasounds as best you can, because ultrasound heats tissue.

Especially early ultrasounds, which are often internal.

Your developing baby will have the internal ultrasound wand placed very close to their brain.

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?

Our pregnancy week by week emails will keep you updated about what’s happening every week of pregnancy!

Simply enter in your estimated due date, and we’ll send you emails based on what week of pregnancy you’re currently at – no need for calculations!

All the best for a wonderful pregnancy – and be sure to bookmark BellyBelly for all your pregnancy questions and answers.

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Kelly Winder is the creator of, a writer, doula (trained in 2005), and a mother of three awesome children. She's passionate about informing and educating fellow thinking parents and parents-to-be, especially about all the things she wishes she knew before she had her firstborn. Kelly is also passionate about travel, tea, travel, and animal rights and welfare. And travel.


  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

    1. Yes. It is very possible. Like myself my last period started on 12/30/15 and I had sex on January 5, 2016. I didn’t get my period so I waited for 2 weeks and went and did a pregnancy test for free and found out that I was indeed pregnant. So it is very possible.

  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

    1. Was your pregnancy accurate? I’m so confused because it was just a couple months after the nexplanon was taken out I got pregnant. But the ultrasound measurement are measuring me to a date or should I say month I hadn’t had sex.

  3. i just wanted to know my last LMP was on 1 december 2015 and i had unprotected sex 0n 10 december 2015 is there any chance to become plz..

    1. Yes there is a chance. Have you still not had a period? If not take a home test. Your not really “late” could be stressing yourself out

  4. If my last period was December 13-17th and last time I had sex which was January 5th (which would’ve been the time i got pregnant) how many weeks am i? I don’t understand this lol

  5. Well mine is way more complicated and I hope you can help me to figure this out. Well my last period was January 14th 2016, but I had my normal skip month of my period in February then I had unprotected sex on February 26th and were now March 27th so that’s no period from February 26th to March 27th.. But don’t get confused about the skipped period in February, because I haven’t had sex till February 26th.. So to make it easier for you to understand this, I had unprotected sex February 26th and were now March 27th so how far a long pregnant would I be ?

  6. on september 2015 i missed my period on the normal date am supposed to see it and during this period i do feel as if i want to vomitt but i later saw my menstration, then i menstrated on october 4th and i did not menstrate again, so i became confused if am pregnant or not, then on january 9th 2016 i went for pregnancy test and i was confired 16 weeks and some days pregnant, when did i become pregnant and how months am i now? pls help.

  7. My last period was between 4-1-16 or 4-18-16 how many weeks would tht make me I just found out yesterday I am pregnant

  8. The start of my last period was April 18th, on May 27th they told me I was 8 weeks and one day but my sac is showing about six weeks. I’m so confuse I need help

    1. I normally get get my period on the 27 of each month I got it early but it lasted a day and half and ever since I’ve been really sick sleeping a lot and craving sherbet and Doritos and extremely emotional

  9. My last period was July 7th-11th I’m 9 days late today woke up with some bleeding and later had some craps my periods are usually heavy and this is lighter the normal could I be pregnant?

  10. help please! Thanks!
    I had a kid back in 2014 after two months i had a mirana iud implanted had it for a while than just this year i decided i wanted another one so i got it out this year in August i had sex begining of september would their still be a chance i can get pregnant quick ?? I normaly had my period at the beginning of every month

  11. My last period was june 22, 2016 up until now september, i still dont have my period.. just wondering how many weeks i am pregnant now?

  12. My date was 21July 2016- 25July 2016 then I had unprotected jst some days after period then August passed by without my period how many weeks could i be??

  13. I thought your article was funny because my little girl was born on October 4th, her due date! How coincidental that you would write that date in your article. Best of luck to all new mothers. I am now expecting my 3rd!

  14. I always get my period on the 28th of every month I am 3 days late took a home pregnancy test clear blue came up positive how many weeks am I

  15. I had my my LMP on the 23 march 2016 that was the first day I start to bleeding I’m usually a 28 days cycle. But I have my partner who I have sex with all the time, however on the 3 of September 2016 I did an ultrasound and it show me I’m 23 weeks pregnant but on the 27 of March even though that was still my period week I had sex with someone else but I was not bleeding heavily just spot can I get pregnant on that day even though my counting ending up to that week I had sex with someone other than my partner?

  16. Hello,

    My last period’s first date was Oct. 06th/ 2016. I did a 2 blood tests and my levels are going up but when I did my ultrasound scan to confirm I was told that I am around 5 weeks pregnant only. Is this possible? Am I pregnant with no risk? My doctor advised me that my fetus is small based on my last period. Is this normal?

  17. I had a period in January, but not sure when. Also I know it wasn’t a regular one. But I didn’t think anything of it, because that happens sometimes with me. But then I started feeling nauseous and my boobs hurting. Then my daughter had her period and I still didn’t start, so I took a pregnancy test and it came back positive. So was wondering how far along I could be.

  18. I had unprotected sex the night before my period (which never came) and then again 9 days ago, it’s been 20 days since my period was supposed to come. I have nausea, cramping, I’m peeing all the time, it’s annoying my coworkers. I can smell, everything, everything. I’m afraid to take a test until I have some opinions on whether or not I should

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