Pregnancy Week & Timeline
Wondering how many weeks pregnant you are? Enter the first day of your last period, or your due date, and we’ll show your current week, your trimester and your estimated due date, plus a gentle timeline of what’s ahead.
Enter a date to see your timeline
We’ll work out how many weeks you are, your trimester and your estimated due date.
This tool is for general planning and information only. It doesn’t provide medical advice, diagnosis or dating. Your midwife, GP or maternity team are your best source of personalised care, always follow their guidance.
How it works
- 1
Pick your starting point
Use the first day of your last period, or your estimated due date if you already know it from a scan.
- 2
See where you are
We calculate how many weeks and days you are, your trimester and how long is left, instantly.
- 3
Follow your timeline
Get a gentle week-by-week timeline of common milestones, and save your due date to your account.
Common questions
How is my due date calculated?
The estimated due date is worked out using Naegele's rule: 280 days (40 weeks) from the first day of your last period. If your cycle is longer or shorter than 28 days, you can adjust it and we'll shift the due date accordingly. If you enter a due date from a scan, we work backwards from that instead.
How many weeks pregnant am I?
Pregnancy is measured in weeks from the first day of your last period, not from conception, so at your dating scan you're usually already around 8 to 12 weeks. Enter your date above to see your exact weeks and days.
When do the trimesters start and end?
The first trimester runs from week 0 to the end of week 13, the second from week 14 to the end of week 27, and the third from week 28 until birth.
Is this a medical tool?
No. This is a general planning tool to help you keep track. Your midwife or maternity team will confirm your dates at your scans, and they're always your best source of personalised advice.
Is my information private?
Yes. Nothing you enter is shared. It stays in your browser unless you choose to save your due date to your own iMumZone account.