Pregnancy Calculator
See how many weeks pregnant you are on any date, which trimester you are in, your estimated due date and when each term milestone falls, from your last period, due date or conception date.
Pregnancy is counted from the first day of your last period, not from conception, so you are already about two weeks along when you conceive. With a last period that started on July 20, 2026 and a 28-day cycle, on October 8, 2026 you are 11 weeks, 3 days pregnant, in the first trimester and 28.6% of the way to an estimated due date of Monday, April 26, 2027, which is 200 days away.
This calculator gives a calendar estimate for general education only. It is not medical advice and it does not diagnose or confirm a pregnancy. Ovulation can happen earlier or later than any estimate, and a first-trimester ultrasound dates a pregnancy more closely than a calendar count. For questions about your pregnancy, your due date or your care, talk to a doctor, midwife or other qualified health professional.
On Thursday, October 8, 2026
11 weeks, 3 days
First trimester, 28.6% of the way to the due date
- Estimated due date
- Monday, April 26, 2027
- Days to the due date
- 200
- Estimated conception
- Monday, August 3, 2026
- Second trimester starts (14 weeks)
- Monday, October 26, 2026
- Third trimester starts (28 weeks)
- Monday, February 1, 2027
- Early term (37 weeks)
- Monday, April 5, 2027
- Full term (39 weeks)
- Monday, April 19, 2027
- Late term (41 weeks)
- Monday, May 3, 2027
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About the Pregnancy Calculator
Gestational age, the weeks and days a pregnancy is described in, starts on the first day of the last menstrual period. Obstetric guidance from the American College of Obstetricians and Gynecologists sets the estimated due date 280 days, or 40 weeks, after that day for a regular 28-day cycle, and this calculator moves it one day later for each day your usual cycle runs over 28, or earlier for a shorter cycle, because ovulation moves with the cycle. From a due date it counts back 280 days to find the date the weeks are measured from, and from a conception date it adds 266 days to reach the due date, so all three routes agree. Trimesters here change at 14 weeks and at 28 weeks; some sources draw the first line a week earlier or later. The term milestones follow the same college's definitions: early term from 37 weeks, full term from 39, late term from 41 and postterm from 42. The due date is the middle of a window rather than a firm day. A first-trimester ultrasound dates a pregnancy more closely than any calendar count, and if it disagrees, your care team will go by the ultrasound.
Frequently asked questions
Why does pregnancy count from my last period instead of conception?+
The first day of a period is a date most people know, while the day of conception usually is not. Counting from it adds about two weeks before conception, which is why a pregnancy counted this way is said to last 40 weeks. If you know your conception date, choose that option and the calculator adds the two weeks for you.
How many weeks pregnant am I if my cycle is longer than 28 days?+
Ovulation tends to come later in a longer cycle, so the estimated due date moves later by the same number of days. With a 35-day cycle and the same last period, the due date is seven days later than for a 28-day cycle, and the weeks pregnant on any date are seven days fewer. Enter your usual cycle length to get that adjustment.
Which trimester am I in?+
The first trimester runs until the end of week 13, the second from week 14 until the end of week 27, and the third from week 28 until birth. The calculator shows the dates each one starts for your pregnancy. Your clinic may use slightly different boundaries, so go by theirs if they differ.
What does full term mean?+
Under the definitions obstetricians use, a baby born from 39 weeks 0 days to 40 weeks 6 days is full term, from 37 weeks is early term and from 41 weeks is late term. The calculator lists the date each stage begins so you can see the window around your due date.
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Free to use on your own site. Paste this snippet where you want the pregnancy calculator to appear — it resizes itself automatically.
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</script><a href="https://manytools.co/health/pregnancy-calculator">Pregnancy Calculator by ManyTools</a>