Pregnancy Calculators UK
Use these UK-focused pregnancy calculators to estimate your due date, current pregnancy week, NHS scan windows, conception timing, IVF due date, and maternity leave planning dates.
This page is for general pregnancy planning and date guidance only. It is not medical advice, diagnosis, or treatment. Pregnancy dates are estimates and can change after a scan or advice from your midwife, GP, or maternity team.
If you have symptoms, concerns, or questions about your pregnancy, speak to your midwife, GP, or maternity team. For urgent help, use NHS 111; call 999 in an emergency. Read how we source and review content in our editorial policy.
Due date and pregnancy week calculators
Start here if you want to estimate your due date, check how many weeks pregnant you are, or build a personalised UK pregnancy timeline.
Due Date Calculator UK
Estimate your baby due date from your last menstrual period or conception date.
How Many Weeks Pregnant Am I?
Find your current pregnancy week and day, then jump to the matching week guide.
Pregnancy Week Calculator
Calculate your pregnancy week and understand what that means for your timeline.
Pregnancy Timeline by Due Date
See trimester dates, scan windows, milestones, and planning reminders from your due date.
Scan and specialist date calculators
Use these calculators for specific pregnancy timing questions such as NHS scan windows, IVF dates, and likely conception timing.
12-Week Scan Calculator
Estimate the usual NHS dating scan window from your pregnancy dates.
20-Week Scan Calculator
Estimate the usual 18 to 21 week anomaly scan window.
IVF Due Date Calculator
Estimate your due date from IVF transfer dates, including 3-day and 5-day transfers.
Conception Date Calculator
Estimate conception date from due date, or due date from conception date.
UK maternity planning calculators
Turn your due date into practical planning dates for work, maternity leave, and later pregnancy preparation.
Which pregnancy calculator should I use?
If you know the first day of your last period, start with the due date calculator. If you already have an estimated due date from your midwife or dating scan, use the pregnancy timeline.
If you are planning around appointments, use the 12-week and 20-week scan calculators. If you are planning work dates, use the maternity leave calculator and check the official GOV.UK guidance before making decisions.
Sources and further reading
Checked for UK pregnancy date and maternity planning guidance in July 2026.
We prioritise official NHS and GOV.UK guidance, then relevant professional-body information where needed.
Source links are checked on the review date shown above. Your midwife, GP, maternity team, fertility clinic, or employer can give advice that is more specific to your circumstances.