Enter your timeline
Choose one method and enter the date. We use UTC dates to avoid daylight saving time drift.
Results
Enter your dates above and press calculate to see your estimated due date and milestones.
Please complete the highlighted fields and try again.
Estimated Due Date
Gestational age today
Equivalent dates
- Equivalent LMP:
- Equivalent conception:
Key milestones
- Start of 2nd trimester (14w0d)
- Start of 3rd trimester (28w0d)
- Early term (37w0d)
- Full term (39w0d)
- Late term (41w0d)
- Postterm (42w0d)
Milestone timing varies by clinical guideline and individual pregnancy factors.
For information only; not a medical diagnosis. Speak with your clinician for personalised guidance.
How to interpret the result
A due date is an estimate. Different input methods can give different answers because they anchor pregnancy timing differently.
Which method should I use?
- LMP (Last Menstrual Period) is common when you know the first day of your last period. Cycle length adjusts the assumed ovulation date.
- Conception / ovulation can be more direct if you tracked ovulation (for example, LH tests or basal body temperature).
- IVF / embryo transfer is often the most precise because transfer date and embryo age are known.
- Ultrasound works from the gestational age measured on the scan date and is often used clinically to confirm or revise dating.
Why cycle length matters (LMP mode)
The “40 weeks” rule assumes a 28-day cycle with ovulation around day 14. If your typical cycle is longer or shorter, the estimate shifts by roughly (cycle length − 28) days.
Mini examples
- Conception date known: enter the ovulation/conception day and the tool adds about 266 days (38 weeks).
- Ultrasound: if your scan says 12w3d on the scan date, we count forward to 40w0d.
- IVF day-5 transfer: enter the transfer date and embryo age 5 days; the tool accounts for embryo age when estimating the due date.
References
FAQ
How is the due date calculated?
From LMP we add 280 days (40 weeks). From conception or embryo transfer we add 266 days (38 weeks). From ultrasound we work backwards from the gestational age on the scan date.
Can I rely on this as medical advice?
No. Only a qualified healthcare professional can provide personalised medical advice. Use this tool as a planning guide and confirm all questions with your care team.