Find your estimated due date, how many weeks pregnant you are and your trimester — calculated from your last period, conception date, an ultrasound scan or an IVF transfer — plus a week-by-week timeline.
Enter the date
Pick how you want to calculate, then enter the date(s). See the estimated due date, how many weeks pregnant you are and the trimester.
=Estimated due date
8 August 2026
Gestational week0 wks 0 days
TrimesterFirst trimester
Conception date (approx.)15 November 2025
Days to due date0 days
The due date is an estimate; only a small percentage of babies are born exactly on the due date. The gestational week is counted from the first day of the last period (or the effective LMP for other methods).
Estimated due date: 8 August 2026 · Gestational week 0wks 0days
◔Week-by-week timeline
Key milestones through the 40 weeks, with a size comparison. Your current week is highlighted.
Week
Trimester
Size
Milestone
4
First trimester
poppy seed
Implantation complete; the pregnancy test turns positive.
6
First trimester
lentil
The heart begins to beat and can often be seen on an early scan.
8
First trimester
raspberry
Tiny arms and legs form; the embryo becomes a fetus.
10
First trimester
strawberry
Vital organs are formed and start to function.
12
First trimester
lime
End of the first trimester; miscarriage risk drops sharply.
16
Second trimester
avocado
Sex may be visible on ultrasound; first flutters can be felt.
20
Second trimester
banana
Halfway point — the detailed anatomy scan is done around now.
24
Second trimester
corn cob
Viability milestone: survival outside the womb becomes possible.
28
Third trimester
aubergine
Third trimester begins; the baby opens its eyes.
32
Third trimester
squash
Bones harden; the baby practises breathing movements.
36
Third trimester
romaine lettuce
Considered early term; most babies move head-down.
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Indicative estimate, not medical advice. The pregnancy calculator uses the standard 280-day rule. The real birth date may differ — consult your doctor for monitoring. Instant in-browser calculation, no account.
✚ Results are for informational purposes and do not replace medical advice. For health decisions, consult a doctor.
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iHow it is calculated
The due date is the start of the gestational clock plus 280 days (40 weeks). With the last period (LMP) that start is the LMP itself; from a conception date it is 14 days earlier; an ultrasound back-dates it from the measured gestational age; and an IVF transfer counts from the embryo's age:
due date = effective LMP + 280 days
For a last period on 1 November 2025: the due date is around 8 August 2026, and conception occurred approximately on 15 November 2025. A day-5 IVF transfer gives the same date when the transfer was on 15 November 2025.
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?Frequently asked questions
How is the due date calculated?
280 days (40 weeks) are added to the first day of the last menstrual period — Naegele’s rule. For example, for a last period on 1 November 2025, the due date is around 8 August 2026.
How is the gestational week calculated?
Pregnancy weeks are counted from the first day of the last period, not from conception. So at the moment of conception you are already about 2 weeks “pregnant”.
How many weeks does a pregnancy last?
A pregnancy lasts on average 40 weeks from the last period. A full-term birth happens anytime between 37 and 42 weeks.
What is Naegele’s rule?
It is the standard method to estimate the due date: to the first day of the last period add one year, subtract three months and add seven days, which equals 280 days.
When did conception occur?
Conception usually occurs at ovulation, about 2 weeks after the first day of the last period, for a regular 28-day cycle. It can vary with the cycle.
What are the pregnancy trimesters?
Pregnancy is divided into three trimesters: the first (weeks 1–13), the second (14–27) and the third (28–40). Each brings different changes for mother and baby.
How accurate is the due date?
It is an estimate. Only about 5% of babies are born exactly on the calculated date; most are born within the two weeks before or after it.
What if I don’t know my last period date?
A first-trimester dating ultrasound gives the most accurate estimate of the pregnancy’s age and the due date, especially if the cycle is irregular or the date uncertain. Switch the method to “Ultrasound scan” and enter the gestational age the sonographer measured.
Can I calculate my due date from an IVF transfer?
Yes. Choose the “IVF transfer” method and pick day-3 embryo or day-5 blastocyst. Because the embryo’s age is known exactly, IVF dating is very precise: the due date is the transfer date plus 261 days (day-5) or 263 days (day-3).
How many weeks pregnant am I?
Count from the first day of your last period (or the effective LMP for the other methods) to today, in whole weeks and days. The calculator shows this as “X weeks Y days” and marks the matching row in the week-by-week timeline.
What does the week-by-week timeline show?
It lists key gestational weeks from 4 to 40 with a size comparison and a one-line development milestone — heartbeat, the 20-week anatomy scan, the 24-week viability mark, and so on. The row for your current week is highlighted so you can see what is happening now and what comes next.
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