Calculate your due date and track NHS antenatal milestones
Calculate Your Due Date
Enter the first day of your last menstrual period (LMP) to calculate your estimated due date.
The NHS uses this date to calculate your 40-week due date
Normal range is 21-35 days. Default is 28 days.
How Many Weeks Pregnant?
Enter your due date or LMP to find out how many weeks pregnant you are.
Conception Date Calculator
Calculate when conception likely occurred based on your due date or LMP.
NHS Antenatal Milestone Tracker
Enter your due date to see your personalised NHS antenatal care schedule.
If you don't know your due date, use the Due Date calculator first
Complete Guide to Pregnancy in the UK
Congratulations on your pregnancy! This comprehensive guide covers everything you need to know about pregnancy care in the UK, from calculating your due date to understanding NHS antenatal services and maternity benefits.
How Your Due Date is Calculated
The NHS uses Naegele's Rule to calculate your estimated due date (EDD). This method adds 280 days (40 weeks) to the first day of your last menstrual period (LMP). The calculation assumes:
A 28-day menstrual cycle
Ovulation occurring on day 14
Conception happening within 24 hours of ovulation
If your cycle is longer or shorter than 28 days, your due date will be adjusted accordingly. For example, if you have a 35-day cycle, ovulation likely occurs on day 21, so your due date would be 7 days later than the standard calculation.
NHS Dating Scan
Your NHS dating scan (10-14 weeks) provides the most accurate due date by measuring your baby's crown-rump length. This measurement is accurate to within 5 days. If your scan date differs significantly from your LMP calculation, the scan date will be used for all future care planning.
Understanding the Three Trimesters
First Trimester
Weeks 1-13
Critical development period. All major organs form. Morning sickness common.
Second Trimester
Weeks 14-26
Often called the "golden period". Energy returns. Baby movements felt.
Third Trimester
Weeks 27-40
Final growth phase. Baby gains weight. Preparation for birth.
NHS Antenatal Care Schedule
The NHS provides comprehensive antenatal care throughout your pregnancy. For a straightforward first pregnancy, you'll typically have around 10 appointments. Second and subsequent pregnancies usually have 7 appointments.
Blood tests for anaemia and antibodies. Anti-D injection if Rhesus negative.
31
Midwife (1st pregnancy)
Review blood test results, measure bump, blood pressure, urine test.
34
Midwife
Discuss birth plan, labour signs, breastfeeding. Second anti-D if needed.
36
Midwife
Check baby's position, discuss birth options, vitamin K for baby.
38
Midwife
Discuss options if pregnancy goes past due date. Check baby's position.
40
Midwife (1st pregnancy)
Discuss induction options, membrane sweep may be offered.
41
Midwife
Membrane sweep offered, book induction date (usually by 42 weeks).
UK Maternity Benefits and Entitlements
Understanding your maternity benefits is essential for financial planning. Here's what you may be entitled to:
Statutory Maternity Pay (SMP)
If you're employed and meet the qualifying conditions:
Weeks 1-6: 90% of your average weekly earnings (no upper limit)
Weeks 7-39: 184.03 per week OR 90% of earnings (whichever is lower)
Total: 39 weeks of paid leave
Maternity Allowance (MA)
If you're self-employed or don't qualify for SMP:
Amount: Up to 184.03 per week
Duration: Up to 39 weeks
Requirement: 26 weeks of work in the 66 weeks before due date
Free NHS Prescriptions and Dental Care
You're entitled to free NHS prescriptions and dental treatment during pregnancy and for 12 months after your baby is born. Ask your midwife for a MATEX certificate at your booking appointment.
When to Contact Your Midwife or GP
Contact your midwife, GP, or NHS 111 immediately if you experience:
Bleeding: Any vaginal bleeding, especially if heavy or with pain
Reduced movements: Baby moving less than usual after 24 weeks
Severe headaches: Especially with vision changes or swelling
Severe abdominal pain: Particularly if one-sided
Waters breaking: Clear or coloured fluid leaking
Signs of pre-eclampsia: Severe headache, vision problems, sudden swelling
Emergency Warning Signs
Call 999 or go to A&E if you have: heavy bleeding with clots, severe chest pain, difficulty breathing, or seizures. These require immediate medical attention.
Frequently Asked Questions
The NHS uses Naegele's Rule to calculate due dates. From your Last Menstrual Period (LMP), add 280 days (40 weeks). This assumes a 28-day cycle with ovulation on day 14. If your cycles are longer or shorter, the due date is adjusted. At your NHS dating scan (10-13 weeks), the sonographer measures your baby's crown-rump length for a more accurate due date, often within 5 days. Only 5% of babies arrive on their exact due date - most are born within 2 weeks either side.
Your NHS dating scan is offered between 10-14 weeks of pregnancy, ideally at 10-13 weeks. This ultrasound confirms your due date by measuring the baby's crown-rump length, checks for multiple pregnancies, and can detect some early abnormalities. You'll also be offered the combined screening test for Down's syndrome at this appointment. Contact your GP or self-refer to maternity services as soon as you have a positive test to book your booking appointment and dating scan.
UK maternity pay depends on your employment status. Statutory Maternity Pay (SMP) for employed women is 90% of average earnings for 6 weeks, then 184.03 per week (or 90% if lower) for 33 weeks. Self-employed women may claim Maternity Allowance of up to 184.03 per week for 39 weeks. You're also entitled to free NHS prescriptions and dental care during pregnancy and for 12 months after birth. Child Benefit of 25.60/week for your first child starts after birth.
For a straightforward first pregnancy, the NHS offers around 10 antenatal appointments. Key milestones include: booking appointment (8-12 weeks), dating scan (10-14 weeks), 16-week midwife check, anomaly scan (18-21 weeks), glucose tolerance test if needed (24-28 weeks), anti-D injection if Rhesus negative (28 weeks), and regular growth checks from 28 weeks. Second pregnancies typically have 7 appointments. Additional appointments are arranged if complications arise.
SW
Sarah Williams
RM, BSc (Hons) Midwifery, Member of the Royal College of Midwives
Sarah is a registered midwife with over 15 years of experience in NHS maternity services. She has worked in both hospital and community settings across England and is passionate about providing evidence-based pregnancy information. This content is reviewed against current NHS guidelines and NICE recommendations.
✓ Expert Reviewed — This calculator is reviewed by our team of financial experts and updated regularly with the latest UK tax rates and regulations. Last verified: January 2026.
Last updated: January 2026 | Verified with latest UK rates