Your due date, current week and trimester from your last period — with milestones along the way.
Gestational age counts from about 2 weeks before conception, so we treat the LMP as 14 days before this date.
Leave “As of” as today to see how many weeks pregnant you are right now, or pick another date.
Gestational age
Enter a date to see your pregnancy week and milestones.
Milestones along the way
| Milestone | Date |
|---|
This is an estimate only — confirm your due date and week with a healthcare professional, ideally with an early ultrasound. Only about 1 in 20 babies arrives exactly on the due date; most arrive within two weeks either side. Seek care promptly for bleeding, severe pain, reduced movement, fever or any worrying symptom.
How to use this tool
Choose “Last period” and pick the first day of your most recent period, or choose “Conception date” if you know it.
Leave it as today to see how far along you are now, or pick another date to check a past or future week.
Your current week and day, trimester, due date and days remaining appear instantly.
The milestone table shows when each trimester ends, the viability milestone at 24 weeks, and when you reach full term at 37 weeks.
Formula & worked example
Last period started 1 January 2026: the estimated due date is 40 weeks later, 8 October 2026. On 1 April 2026 you are 12 weeks and 6 days pregnant, in the first trimester, with the first trimester ending 8 April 2026 and full term reached 17 September 2026.
Limitations — read this before you rely on it
This is an estimate, not medical advice and not a diagnosis. It assumes a regular cycle and a known last period or conception date; irregular cycles, recent hormonal contraception and fertility treatment can shift the true dates. Only a healthcare professional, ideally with an early ultrasound, can confirm your due date. Seek care promptly for bleeding, severe pain, reduced fetal movement, fever or any worrying symptom — do not rely on this calculator for medical decisions.
Frequently asked questions
Enter the first day of your last period, or your conception date if you know it. The due date is 40 weeks (280 days) from the last period, or 38 weeks (266 days) from conception.
Pregnancy is counted from the first day of your last period, even though conception happens about two weeks later. So at a positive test you are usually already around 4–5 weeks pregnant.
First trimester: weeks 0–13. Second: weeks 14–27. Third: week 28 until birth. The tool shows your current trimester and the dates each one ends.
Only about 1 in 20 babies arrives exactly on the due date. Most arrive within two weeks either side, and a pregnancy is considered full term from 37 weeks.
Early ultrasound dating is more accurate than the last-period method, especially with irregular cycles. Ask your clinician or midwife to confirm your dates at your first appointment.