Latest Updated 17 March 2026
* Ranges from: 22 to 44 days. 28 Days is the average for most women, leave at 28 days if unsure. This is not a diagnosis. The calculations that are provided are estimates based on averages.
Pregnancy Score
—
—
Your pregnancy progress: —
Your estimated due date is the result given by our due date calculator, showing the likely date your baby will arrive. This pregnancy calculator uses the first day of your last period or conception date, based on NHS guidelines. While most pregnancies last 37–42 weeks, only a few babies arrive on the exact due date.
The estimated date you receive helps plan appointments and scans, and your results may change after an ultrasound. Always use your due date calculator as a guide, not a guarantee, and speak to your midwife for personalised advice.
Your estimated dates from the due date calculator give a week-by-week view of pregnancy milestones. The pregnancy calculator outlines key fetal development stages, while referencing screening periods and typical checks based on NHS guidelines. The NHS pregnancy calculator and related methods support planning for scans and appointments, use your pregnancy calculator results to stay prepared.
(Weeks 1–12)
(Weeks 13–26)
(Weeks 27–40)
Your due date calculator supports understanding these steps, but always review the latest NHS milestones for updates.
After a positive pregnancy test, use the due date calculator or pregnancy calculator to estimate your baby’s arrival. Next, contact your NHS maternity service or a midwife to start care. You can often self-refer directly; there’s no need to see a GP unless you have ongoing health issues.
Your first midwife appointment uses your due date calculator estimate and covers medical history, and screenings. Be ready to share information from your pregnancy calculator results, and check NHS links for booking forms, appointment timelines, and what to expect.
The due date calculator provides an estimate, not an exact prediction. Only around 4% of babies arrive on their calculated due date. Results from any NHS based pregnancy calculator or methods may be less accurate if you have irregular cycles, uncertain dates, or conceived by IVF.
Early ultrasound scans are often more precise than traditional due date calculator methods, your NHS team may update your dates after these appointments. Use the pregnancy calculator and NHS guidance as a planning tool, but always check with your midwife, as your real delivery date may vary by days or weeks.
After using the due date calculator or pregnancy calculator, follow these steps:
These steps ensure your due date calculator result is used effectively for appointment planning and personalised pregnancy care.
Weeks 8-12
Milestone/Check
First appointment, due date calculator review, blood tests, early scan
Week 16
Milestone/Check
Routine check, fetal growth, discuss vaccinations
Week 20
Milestone/Check
Pregnancy calculator estimate reviewed, anomaly scan (detailed ultrasound)
Week 25
Milestone/Check
Health check, discuss any symptoms and plans
Week 28
Milestone/Check
Blood tests (anaemia, glucose), routine check; vaccinations offered
Week 31
Milestone/Check
Growth check, review of baby’s movements and results
Week 34
Milestone/Check
Health and birth planning, mental wellbeing review
Week 36
Milestone/Check
Physical examination, position/birth options, symptom discussion
Week 40+
Milestone/Check
Post-due date planning, induction options, further scans if needed
Can’t find your answer? Email us and we’ll get back to you as soon as possible!
The due date calculator provides an estimated date, only about 4% of babies are born on that specific day, so use it as a guide.
Yes, early scans often provide a more accurate date than the pregnancy calculator alone, and your NHS team may update your details
If you conceived through IVF, your NHS team and due date calculator will use the date of embryo transfer for best accuracy.
Speak to your midwife; an ultrasound can help confirm your stage.
Accuracy relies on entering correct dates; for best results, combine the pregnancy calculator tool with clinical scans.
Irregular cycles may affect estimates, use the due date calculator and ask your midwife about NHS scans for extra precision.
The date may change based on early scans, cycle length, or IVF details, so update your pregnancy calculator information as care continues.
Check NHS websites or local maternity teams for contacts and resources.
Bring information from your due date calculator, medical history, and details of any medications. Your team will review your pregnancy calculator results.
Take a test from the first day of a missed period, then use the pregnancy calculator and consult NHS advice for next steps.
No spamming! Only the best content summary from the month on all medical topics
