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

  • Image of young boy meeting baby sibling for the first time.


    Tips for staying connected when you have a newborn

    It might not be exactly how you pictured it, bringing your baby home with social distancing measures in place. But it's important to do whatever you feel like when it comes to marking the first few weeks and staying connected with the people you love. Here are some ideas, but please be kind to yourself and don't expect too much.

  • Illustration of woman looking in the mirror at her reflection


    Dear pregnant me...let's talk about your body after birth

    Your tummy will deflate and the swelling will ease, and whilst your body may not be the way it once was, it will always be your baby's first home. There's something beautiful about that, and that is something beautiful about YOU.

  • Illustration of woman fighting back against a cloud of unwanted comments


    Dear pregnant me...let's talk about unwanted advice

    Things I wish I had known when I was pregnant about...unwanted advice. People generally mean well, but at the end of the day, you and your partner (if you have one) are the only ones who get to decide how to raise your baby.

    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 Anonymous (not verified) on 23 Mar 2017 - 15:19

      Can i have cough and cold medication while pregnant i am 4 weeks in to the pregnancy.

    • By Midwife @Tommys on 23 Mar 2017 - 16:12

      Hi, It is good practice to consult your GP or midwife before taking any medication in pregnancy, particularly in the first trimester.
      Most coughs and colds resolve on their own and best advice is to drink plenty of fluids, get some rest and eat a healthy diet with plenty of fruit and vegetables. You could also try hot lemon and honey drinks or ginger tea. You may find this link helpful.
      I hope this helps. Best wishes

    • By Anonymous (not verified) on 17 Mar 2017 - 10:37

      I'm 33weeks pregnant . I have nose bleed since yesterday. Is this normal

    • By Midwife @Tommys on 20 Mar 2017 - 09:16

      Hi there. Yes, nosebleeds do tend to occur more often during pregnancy. Pregnancy can cause the blood vessels in your nose to expand, and your increased blood supply puts more pressure on those delicate vessels, causing them to rupture more easily. If they do not clot and stop, then seek medical attention via GP/walk in centre. But if they are just on and off, then this is nothing to worry about, although inconvenient. Take care of yourself

    • By Anonymous (not verified) on 2 Sep 2016 - 10:41

      Is it normal for ankles to swell early in pregnancy. I am 40, work full time and active.

    • By Midwife @Tommys on 8 Sep 2016 - 09:55

      Hi, some ankle swelling can be normal especially when the weather is warm and you have been active during the day. Try to keep well hydrated and take some time to rest, elevating your legs. If you sit for large parts of the day for work then try flexing your feet up and down regularly and stretching out your legs. If one leg is more swollen than the other then see your GP for a review. If the swelling continues it is worth seeing your midwife for an antenatal check for BP and urine review, though this is more applicable if you are in your second or third trimester. If you would like further advice please call on 0800 0147 800

    • By Midwife @Tommys on 10 Aug 2016 - 14:40

      It is not possible to ascertain if you in early or late pregnancy from the information provided, however I will presume you are in the first trimester. It is not uncommon to have some spotting in the first trimester and some of the harmless causes are an implantation bleed (as the fetal sac settles into the womb) and on intercourse when a cervical erosion may have been the cause . If the bleeding persists and you start to develop abdominal pain, it may unfortunately mean you are miscarrying, with most miscarriages occurring within the first 12 weeks of pregnancy. If this occurs you should seek medical help. If you are concerned please contact one of our Midwives on the pregnancy helpline on 0800 0147 800. We are here from Monday to Friday from 9am till 5pm & happy to have a chat with you to help alleviate your concerns

    • By Anonymous (not verified) on 10 Aug 2016 - 07:52

      I had a little blood lst normal pls. Thanks

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