Pregnancy Due Date Calculator

Use our Pregnancy Due Date Calculator to find your estimated due date and see major milestones throughout pregnancy


Select first day of your last period *

Frequently Asked Questions about Pregnancy Due Date Calculator

How We Calculate Your Pregnancy Due Date ?

Due date is the estimated date of delivery. The actual delivery date may be the same or different due to many other factors related to pregnancy.Here's a pregnancy calculator that will help you calculate due date.
This calculator uses the LMP method. by LMP method you can calculate the due date by adding 40 weeks i.e 280 days to first day of your last menstrual period (LMP). Pregnancy is considered from first day of your last menstrual period (if pregnant), menstrual period is the first week of the pregnancy and lasts for approximately 40 weeks, i.e. 9 months 7 days. So, adding this length from the first days of your LMP gives your estimated date of delivery (EDD). This method is known as Dr. Nagele's rule.

What is pregnancy due date or expected date of delivery (EDD) ?

The expected date of delivery (EDD) is the date on which you are likely to give birth to your baby. It is calculated on certain assumptions and gives an approximate date, helping you to prepare for the ‘D’ day.
Around 280 days or 40 weeks is what is considered for calculation. To be exact, it is nine and one-third months or 10 lunar months.

Why is due date calculated from last period ?

LMP is the first day of your bleeding during the last menstrual period. You bleed as the uterus sheds the lining formed during the previous cycle. Ovulation occurs around two weeks from LMP, and that is when you become fertile. If fertilization occurs during this cycle, the uterine lining (endometrium) grows to accommodate the baby, thus making you miss your next period.
LMP is also considered for calculation because the date is easier to remember!

How accurate are pregnancy due date calculators ?

Pregnancy due date calculators provide estimates that are generally accurate within a range of two weeks. However, the actual delivery date can vary based on individual factors and the accuracy of the input data. It's important to remember that it's an estimation, not a guarantee.

Can a due date calculator work for women with irregular periods ?

Due date calculators may be less accurate for women with irregular periods. If you have irregular cycles or are unsure of your last menstrual period, it is recommended to consult with a healthcare provider for a more accurate estimate. They can consider additional factors to provide a personalized calculation.

What is a pregnancy due date calculator ?

A pregnancy due date calculator is a tool used to estimate the expected date of delivery (EDD) based on the first day of a woman's last menstrual period (LMP) or other relevant information. It helps provide an estimation of when your baby might arrive.

Can a due date calculator predict the exact day of delivery ?

No, a due date calculator cannot predict the exact day of delivery. It provides an estimate based on the average length of a full-term pregnancy, which is around 40 weeks from the first day of the last menstrual period. However, the actual delivery date can vary.

C-Section and Due Date Calculator

In the event of a C-section delivery, whether it is a planned C-section or an emergency C-section delivery, using a pregnancy calculator can still be extremely beneficial. The milestones provided by the calculator remain valid and useful in tracking the progress of your pregnancy. However, it's important to note that the exact date of your C-section will be determined by your healthcare provider, who will take into consideration your specific medical conditions and circumstances.
Most elective C-sections, are typically scheduled near full term, which is around 39 to 40 weeks of gestation.

Should I rely solely on a due date calculator for determining my due date ?

It's always best to consult with a healthcare provider to determine your due date accurately. They can consider various factors, such as ultrasound measurements and other medical information, to provide a more precise estimate tailored to your specific circumstances.

Can a due date calculator determine the gender of my baby ?

No, a due date calculator cannot determine the gender of your baby. Its purpose is solely to estimate the expected due date based on the provided information. Determining the gender requires other methods, such as ultrasound or genetic testing.

What if the estimated due date from the calculator does not match my ultrasound measurements ?

Ultrasound measurements are considered more accurate for estimating the due date. If there is a significant difference between the estimated due date from the calculator and the ultrasound measurements, your healthcare provider will use the ultrasound information as a more reliable reference.

Can I use a due date calculator if I have had fertility treatments or IVF ?

If you have undergone fertility treatments or in vitro fertilization (IVF), the conception date may not align with the date of your last menstrual period. It is best to consult with your fertility specialist or healthcare provider for an accurate due date estimation tailored to your specific circumstances. Dedicated online IVF due date calculators are also available.

Are there any other factors that can affect the accuracy of a due date calculator ?

Certain factors, such as maternal age, maternal health conditions, irregular periods, and variations in fetal development, can affect the accuracy of due date calculators. These tools provide estimates based on averages and may not account for individual variations. Consulting with a healthcare provider can help address these factors.

Can I still use a due date calculator if I don't know the exact date of my last menstrual period ?

If you don't know the exact date of your last menstrual period, it is recommended to consult with a healthcare provider who can help you estimate your due date based on other information, such as the date of conception or ultrasound measurements. They can use alternative methods to provide a more accurate estimate.

Reviewed By

Dr Sobia Mohyuddin

MCPS, FCPS, MRCOG, Consultant Obstetrics & Gynaecology

Doctor Sobia Mohyuddin is a highly skilled and experienced Obstetrician and Gynecologist, with 25 years of training and experience in renowned, large institutions. She holds the position of Associate Professor and Fellow at the College of Physicians and Surgeons Pakistan. She is also a member of the Royal College of Obstetricians and Gynecologists (UK).