Find out your due date with our calculator

Just found out you're pregnant? Work out when your baby's due with our due date calculator.

📅 Calculate your due date

Tommy’s funds pregnancy research that saves babies’ lives and we’d love to keep you posted with our research news, campaign activities, fundraising events and appeals. Your details will only be used by Tommy’s – we will never give your information to other organisations to use for their own purposes. Read our full data protection and privacy policy for further information. You are free to change your mind at any time.

If your cycle is shorter or longer than 28 days, please adjust the number above.


How to use the pregnancy calculator

To find your due date you just need to select the date of the first day of your last period on our pregnancy calculator tool and click 'submit.'

You will then receive your estimated due date and the option to sign-up to our pregnancy email. This weekly email gives you fun pregnancy facts, useful tips and great recipe ideas to help you and your baby have the healthiest possible pregnancy.

Are you in early pregnancy? Find out all you need to know about week 4 onwards here.

How accurate is the due date?

The pregnancy calculator gives you an approximate due date, which it works out your due date by adding 280 days (40 weeks) to the first day of your last menstrual period (assuming a 28 day cycle, it is adjusted for longer or shorter cycles). Your period and ovulation are counted as the first two weeks of pregnancy. If you have the baby on your due date, your baby has been growing for 38 weeks, not 40, but you are still classed as 40 weeks pregnant. 

Will I get a more accurate due date later in the pregnancy?

You will have your first appointment with the midwife, the 'booking appointment', between 8 weeks and 12 weeks pregnant. Here you will be given a scan and receive an accurate date for your baby's birth. But if you're impatient to know when your baby will arrive, then our calculator tool gives you an estimate due date without the wait.

Read more

Pregnancy in the news

    Last reviewed on April 1st, 2014. Next review date April 1st, 2017.

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    Please note that these comments are monitored but not answered by Tommy’s. Please call your GP or maternity unit if you have concerns about your health or your baby’s health.
    • By Olubukolaowokotomo (not verified) on 17 Apr 2020 - 16:36

      Am 37weeks +6days pls I need to know my due date

    • By Precious (not verified) on 7 Mar 2020 - 12:07

      Want to know my due date. Last date of period was on 18th January 2020

    • By Anonymous (not verified) on 2 Feb 2020 - 00:11

      I am pregnant and my due date is 22nd Feb 2020

    • By Ebru (not verified) on 4 Mar 2020 - 21:26

      I am 7 weeks pregnant and I thought I was just getting fat and I went to the gp for a check up and he was like how’s your babys and I was like WHAT and now I am a mother to 2 healthy twins at age 15

    • By Ariana (not verified) on 4 Nov 2019 - 06:51

      Thank you for such an informative blog post

    • By ruth (not verified) on 3 Jan 2020 - 10:50

      may 23 2019

    • By Pauline ohaezu (not verified) on 18 Oct 2019 - 15:36

      Iast 29 September 2019 today 3

    • By P johnsoni (not verified) on 14 Oct 2019 - 14:49

      I get pregnant 3 January wish month I should have my baby?

    • By Olivia (not verified) on 20 Sep 2019 - 14:10

      My last peroid was 13th August and i missed my peroid 9th of 28days,how many weeks or month pregnant are my i?urgent please...thank

    • By Anon 101 (not verified) on 10 Sep 2019 - 00:39

      In Feb i took the plan b the day after having unprotected sex, i didn't get my regular period, just spotting here and there, i then took 2 pregnancy tests a month later in March and both were negative, up until this day i haven't got my period, I've started seeing some in April and we've been active unprotected though, and today i found out I'm 34 weeks and 5 days pregnant, now is it possible for the guy i was with in Feb to be the father, keeping in mind that the tests were negative, please help me. I'm not familiar with these things weeks of pregnancy and things, I'm stressing.

    • By mary (not verified) on 29 Aug 2019 - 09:18

      please I saw my period on 16th of December 2018 And now am Eight months gone just want to know my edd cos am confused don't know when I took in

    • By Mary (not verified) on 2 Aug 2019 - 14:19

      The messages are really educative and encourages me most

    • By lulu (not verified) on 25 Jul 2019 - 14:39

      i had last period may 11,2019 altrasund showed 6week but my calculaton pls tell me the real one

    • By Modester (not verified) on 24 Jul 2019 - 18:07

      Pls I am 25 weeks pregnant. I use to have wet paint after stress. Is it normal?

    • By Gloria (not verified) on 19 Jul 2019 - 13:32

      I had my periods on the 23th -27th June 2019
      And then had unprotected sex on the 5th /6th of July 2019 and then had some spotting on the 7th. And today am having periods again yet l thought l had conceived. What could be the problem

    • By Lilly (not verified) on 11 Jul 2019 - 21:09

      Good day. I had sex on the 19th October and then again on the 23 November. I had bleeding on the 15th of November but now I am not sure if it was my period or implantation. The ultrasound says that I am due on the 8th August which says I had sex around the 10th of November which is not true. Which date is likely to be my conception date?

    • By Cassy (not verified) on 3 Sep 2019 - 21:10

      I saw my period 19 of July but I did see last month I know am pregnant but how month do u think am i

    • By Yommy (not verified) on 19 Jun 2019 - 15:19

      My last period was on 14th of November and I did my first scan on the 5th of January which says my edd is on the 4th of September and ever since then all the scan I have been doing do gave me 21st of August as my edd expect those ones I did last week one gave me 28th of August and 4th of September am really confuse, really want you yo help out with the accurate edd

    • By mimie,, (not verified) on 12 Jun 2019 - 16:22

      my last mestural was 20th Nov,,,wen z de due date of my delivery?

    • By Ashley Alli (not verified) on 30 Mar 2019 - 17:09

      I’m not sure if I’m pregnant or not not my last period was on February 23-25 and I was supposed to get it on March 25-29. When should I take a test?

    • By Katie (not verified) on 9 Aug 2019 - 08:58

      I would definitely do a pregnancy test as I'm 34yrs old and now 11wks pregnant, I was trying for so long that even a period felt like a loss. Dont keep yourself guessing, do a test so you know exactly were you stand. If you are wanting a baby, I wish you all the best and hope God does bless you to X

    • By Joy (not verified) on 26 Mar 2019 - 05:43

      I had my last period on 13th December 2018.Today makes it 3months and 2weeks.Does that means I got pregnant 2days after my last period which is 17th of December?.

    • By Becky (not verified) on 31 Jan 2019 - 21:02

      Hi there I’m slightly confused , my last period was 8th may till 13th may , My midwife / ultrasound said I was 12 weeks pregnant but that means I was pregnant just 3 days after my period started as it led to the 16th may , or is the first 2 weeks not counted as being pregnant ? I’m nearly due now and still slightly confused

    • By Midwife @Tommys on 1 Feb 2019 - 10:24

      Dear Becky,
      The most accurate way of dating a pregnancy is ultrasound scan at about 12 weeks gestation. This scan in affect has two weeks added on to it, so will usually date back to around the time of, or just after your period. I hope that makes things a little clearer.
      Best wishes
      Tommy's midwife

    • By Star (not verified) on 5 Oct 2018 - 19:18

      Is it possible for a sexual.intercourse done in 29th december 2017 to produce a baby on 13th september of a 2018 as the last menstruation cycle was 9th december 2017 ?

    • By Midwife @Tommys on 9 Oct 2018 - 12:01

      Yes these dates would indicate the pregnancy was 40 weeks plus 3 days.

    • By Brilliant (not verified) on 23 Jun 2019 - 18:56

      I first see my period at date 1 may last month . Will it mean am pregnant now

    • By tina (not verified) on 2 Aug 2019 - 19:41

      the first day of my mistranslation was on 27 June 2019 and up to now have not see my period

    • By Angha (not verified) on 29 Aug 2018 - 10:29

      Tell me about how to control gestetional dibeties

    • By Midwife @Tommys on 31 Aug 2018 - 14:01

      Hi Angha,
      We have lots of information on our website about managing gestational diabetes here:
      You should also be supported by a specialist midwife and being having regular scans too.
      Best wishes
      Tommy's midwife

    • By Agbo Dester (not verified) on 3 Jun 2018 - 19:25

      I am 35 weeks pregnant and I have been having abdominal contractions since yesterday night. It contracts so frequently that makes me uncomfortable and somehow painful, could it be premature labor that I am going into. Please I need your help

    • By Midwife @Tommys on 4 Jun 2018 - 16:49

      Braxton hicks contractions are common at 35 weeks. We like to call them practice contractions because the uterus goes hard for a short time and then relaxes. Usually this is not associated with pain. If you think that you may be in labour, please call your maternity unit who will ask you some questions and assess over the telephone if you need to be seen. Best wishes to you

    • By Rich (not verified) on 29 May 2018 - 09:01

      Hey, I am now 23 weeks pregnant. But I can't show my baby bump yet. Am I normal ?

    • By Midwife @Tommys on 30 May 2018 - 16:03

      Hi Rich
      Bumps come in all shapes and sizes. As long as your midwife is not concerned about the measurement of your bump (she/he should measure your bump from 16 weeks onwards) then there is no concern. If there is a concern over fetal growth, you will be referred for an urgent growth scan.
      Take care
      Sophie,Tommy's Midwife

    • By Ruthie (not verified) on 15 Aug 2019 - 16:03

      Go Into The Scan En They Check Why?

    • By Bee (not verified) on 18 May 2018 - 12:32

      Hi i have been having lower abdominal pains, i'm 11 weeks plus.
      what could this be?

    • By Midwife @Tommys on 18 May 2018 - 16:31

      Hi Bee,
      Sometimes lower abdominal pain can be normal in pregnancy as it is common to get some cramps and stretching type pains however if this is on going, and particularly if you are having any bleeding or any other symptoms then do contact your GP for review.
      Best wishes,
      Tommy's midwives

    • By Nelly (not verified) on 4 Feb 2018 - 18:24

      I tested positive but i see blood each time I went to urinate it have lasted for some days now am I really pregnant

    • By Midwife @Tommys on 5 Feb 2018 - 15:26

      Hi, I hope you are OK. Sometimes a miscarriage can happen really early and can appear like a normal period. Try doing another test in a week to see if you are still pregnant. If you have abnormal bleeding or pain please see your doctor for advice.

    • By Kat (not verified) on 18 Jan 2018 - 01:11

      My last period was 10th December not had one since but pregnancy test negative

    • By Midwife @Tommys on 19 Jan 2018 - 13:01

      Hi Kat,
      Testing for pregnancy can be different for everyone, and for some pregnancy is detected a little but later especially if you have a longer cycle. It maybe worth testing in about a week, if this is still negative and your period does not come then see your GP who may do a blood test which is more sensitive. If you are not already, then we would strongly advise for you to be taking a folic acid supplement. Take care x

    • By Anonymous (not verified) on 13 Dec 2017 - 21:59

      I’ve just found out I am pregnant ( yay )
      But I’m struggling to work out my due date.
      The test said ‘1-2 weeks ‘
      My cycle is inconsistant and not a typical 28 day.

      My last period was 5th-9th Nov. I kept track of my ovulation day which was the 28th nov.
      I have read that the GP would normally go by the date of your last period however as I know my ovulation day and it would time perfect with the pregnancy test 1-2 weeks, should I just go by this instead ?

      Thank you

    • By Midwife @Tommys on 14 Dec 2017 - 09:42

      Using your last menstrual period (LMP)date of 5th Nov, you are approx 5 weeks pregnant. However, if your cycle length is inconsistent then it is likely to be less than that. It would be sensible to make a GP appointment as they would go by your LMP date and then this may change when you have your first Ultrasound scan. It doesn't matter too much if there is a discrepancy in dates- the midwives and obstetric doctors will always go by the scan measurements and dating to give an accurate gestation and due date.
      Congratulations and please take care of yourself!
      Sophie,Tommy's Midwife

    • By Anonymous (not verified) on 2 Dec 2017 - 00:28

      I am waiting for 2 months for my periods. All my blood tests and urine tests were negative. Started getting faint positives since last two days in morning urine / concentrated urine (in bladder for atleast 4 hours) and negative when urine is diluted. Doc did urine test today when it was diluted and told me it is negative. Sent to an ultrasound before 2 days and it showed nothing. But I am getting faint positives only since two days and I’m using same brand which gave me negative results earlier. Why ultrasound didn’t detect my pregnancy? Am I too early to go for ultra? Why my urine test would fail when I get faint positives in morning urines / concentrated urines?

    • By Midwife @Tommys on 4 Dec 2017 - 12:04

      Hi, It is possible though very rare to get false positive pregnancy tests. This can happen if you have blood or protein in your urine or if you are on certain medications. Usually a blood test will confirm a pregnancy before a a urine test but it does have to be sent to the lab for analysis and this takes time. Best advice is to wait a week and repeat the test. If you are still getting positive tests or have any tummy pain you should see your doctor again.

    • By Krit (not verified) on 30 Nov 2017 - 23:22

      I haven’t got my period since 65 days. Though I have pcod I have been regular on my date for atleast 6 months. Last month I did multiple hpt and one beta blood test and all turned to negative . Last week again I did a blood test and multiple hpt it was negative. From yesterday morning I started getting faint positives in my first morning pee. I also got positive when I keep the bladder full for atleast 4 hours. But all the positives are faint. Could I be pregnant? I used the same brand pee stick since I started testing.

    • By Midwife @Tommys on 1 Dec 2017 - 11:37

      Any positive pregnancy test is taken as confirmation of a pregnancy, it maybe that the pregnancy test is only just picking up a very early pregnancy. It maybe worth repeating the pregnancy test in a week to allow for the hormone levels to rise significantly more to confirm the pregnancy. Your other option would be to see the GP for a blood test which would confirm a pregnancy as this is more sensitive. If you are not already, we would also advise that you are taking a folic acid supplement.

    • By Anonymous (not verified) on 30 Mar 2017 - 18:56

      Ive just found out i am pregnant but want to work out the conception date because there is two different times. One was in my ovulation week that i worked out from my cycle and the other one was 2 weeks later, 2 days before my period was due. I got a positive pregnancy test 2 days after my missed period (which was only 4 days after this second time) will i more than likely have conceived on this first intercourse? Whats the earliest you can get a positive pregnancy test?

    • By Midwife @Tommys on 31 Mar 2017 - 15:07

      It does sound more likely that conception would have occurred during the first time of intercourse however this cannot be guaranteed as there was no period in between.

    • By Precious (not verified) on 25 Mar 2017 - 03:59

      I want to know my due date

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