Due Date Calculator – Mamas & Papas UK

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Due Date Calculator

Find out when your little one is due with our calculator.
When was the first day of your last period?
For example, 15 June 2021
How long is your cycle?
Everybody's different - tell us how many days your cycle lasts on average
*This is an estimated date and might change when you go for your dating scan. If you think you might be pregnant, get in touch with your doctor.
Your little one is due on...


Not looking right? Recalculate
How to use our
Due Date Calculator
1. Check your calendar and tell us the first day of your last period
2. Enter your average cycle length – this could be more or less than 28 days
3. Hit ‘Tell me my due date’ and we’ll give you an estimated date
How do we calculate...
your due date?
A full-term pregnancy can be anything from 37 weeks to 42 weeks, and starts from the first day of your last period, so we use your menstrual cycle to work out an estimated due date.
When you’re around 12 weeks pregnant, you’ll be invited for a dating scan, where a sonographer will measure your baby and give you a more accurate date based on their size. This might be different from the date you’ve been given based on your cycle, and still isn’t a perfect prediction – as babies can come in all shapes and sizes!
Beginning your pregnancy journey...
What’s next?
If you think you might be pregnant, it’s important to speak to your doctor as soon as possible. They’ll then talk you through your next steps, and help you get booked in with a midwife.
Your first midwife appointment is known as a booking appointment, and usually happens when you’re between 8-10 weeks pregnant. They’ll go through your medical history and be able to advise on everything from your diet to your changing body – they’ll also get you booked in for your dating scan.
Your pregnacy, your story
Step by step