HomePregnancyPregnancy Due Date Calculator: Estimate your delivery date

Pregnancy Due Date Calculator: Estimate your delivery date


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Curious to know when you will likely deliver or have your baby? Be it a pregnancy, through normal conception, or IVF, a pregnancy due date calculator can help you record your pregnancy timeline with the details you provide to this excellent automated tool.  

Isn’t it exciting for the couple to spend time with their baby after delivery? And the availability of this tool online allows the expecting couple to plan their pregnancy, antenatal tests, doctor’s appointments, and check on their leaves to be taken for after delivery. They can rejoice in the most precious moments of being with the baby by estimating their due date. 

The pregnancy due date calculator can help you know your approximate due date by four different means

  1. Know your pregnancy delivery date with the help of your first day of last menstruation
  2. Use your conception date to calculate your due date 
  3. For parent(s) conceiving through IVF- IVF transfer date can do the needful
  4. Even your ultrasound scan can be helpful to estimate the due date.

Through this article, you will better understand the calculations of the due date calculator using the ways mentioned above.

Calculate with your first day of last periods

For most pregnancies, the pregnancy duration is around 40 weeks from the first day of your last menstrual period (LMP). So, typically you can estimate your due date from your last menstruation by,

  • Adding up 40 weeks or 280 days to your first day of LMP


  • Subtracting three months to the first day of your LMP and adding 7 days to it. 

While you enter your LMP details, you will need to include the length of your menstrual cycle. In the case of irregular periods, the average length of three consecutive menstrual cycles can help figure out the average menstrual cycle length. 


 First Day of LMP + 40 weeks or 280 days


(First day of LMP – 3 months) + 7 days

By using the conception date

Typically, most pregnancies last for 40 weeks and 38 weeks post-conception (the time when the gametes fertilize). If you know the ovulation period through the ovulation calculator, the conception date is just a day added to your ovulation date. You can also track the indicators of ovulation such as

  • Cervical mucus discharge
  • Mild lower abdominal cramps
  • Breast tenderness
  • Changes in basal body temperature
  • Libido changes to know the ovulation time.

Select conception date to add the details, and the due date calculator will calculate your most likely delivery date. 

PREGNANCY DUE DATE= Conception date + 266 days

Pregnancy through IVF? Embryo transfer date can help.

Mothers conceiving through In Vitro Fertilization (IVF) can use their embryo transfer date to know their due date. Normally, the embryos are transferred after day three or day five of egg retrieval or fertilization. Select whether the embryos were transferred after day three or day five of fertilization and get your due date to plan your pregnancy.


Embryo Transfer date + 263 days (for day three embryos)


Embryo Transfer Date + 261 days (for day five embryos)

Ultrasound scan reports act as clues. 

What if you are not sure when you have conceived or ovulated? Nor have you recorded the day of your last menstruation. Other clues like the ultrasound scan reports can help you and your healthcare practitioner determine the due date at your first prenatal appointment. 

  • An early ultrasound during the first trimester is done routinely when
  • The woman is above 35 years.
  • Have a history of miscarriages or pregnancy complications
  • The woman has irregular periods.
  • Or the Physician is unable to determine the due date through a physical exam and LMP.
  • Pregnancy milestones captured in ultrasound, such as the first time the baby’s heartbeat is heard (around week 9 or 10) and the first feel of the baby’s movements (18 and 22 weeks), can also help you know your pregnancy due date.
  • The fundal height– the measurement from the pubic bone to the top of the uterus also helps confirm the due date. 
  • The CRL of the fetus measured during the ultrasound can also help calculate the gestational age and the pregnancy due date.

    Also Read: https://pregajunction.com/blog/types-of-baby-delivery-during-pregnancy/

Frequently Asked Questions

1-When is pregnancy considered full term?

Pregnancy between 37 weeks to 42 weeks is considered a full term. On average, most pregnancies last for 40 weeks of gestation. 

2-Can my due date change?

The due date calculated through the online tool is an estimation, and your doctor can change it as and when the pregnancy progresses due to the following reasons.

  • It may be due to irregular periods that the early ultrasound taken in the first trimester showed up to be a second-trimester ultrasound scan.
  • Abnormal fundal lengths may be due to the alpha-fetoprotein shooting up than the usual range. 

Your Obstetrician can help determine your due date depending on your pregnancy. 

3-How accurate are due dates calculated through ultrasound scans?

Evidence suggests that ultrasound scans are accurate due date predictors during the first and second trimester. And also, ultrasound scans have an error margin of nearly 1.2 weeks.

Pooja N Swamy (M.Sc Biomedical Sciences)
Pooja Holds Master's Degree in Biomedical Sciences from Vellore Institute of Technology. She believes in strong research and clear understanding over the subject. Always determined and focussed with a thirst to learn new things. Hardworking, flexible and grounded to align with the goals.


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