Pregnancy Due Date Calculator

Calculate Your Due Date and Track Weekly Pregnancy Milestones

Calculate Based On:

Last Menstrual Period Date:

Gestational Age at Ultrasound:

Embryo Age at Transfer:

Please enter the required details and click Calculate.

Calculation Examples

Calculation Case	Result
Last Period: Jan 1st	Due Date: October 8th
Conception Date: May 15th	Due Date: February 5th
IVF Transfer Date	Accurate to embryo age (3 or 5-day)

How to Calculate Your Due Date

Our calculator estimates your delivery date using Naegele’s Rule. This standard obstetric method determines the 280-day (40-week) gestational timeline by following the formula: $$\text{EDD} = \text{LMP} + 7\text{ days} + 9\text{ months}$$ If you know your exact ovulation date, the tool adjusts the calculation to 266 days from conception for higher precision.

Understanding Your Pregnancy Timeline

Pregnancies are approximately 40 weeks long (gestational age) from the LMP (according to most obstetrical coding) and are typically divided into trimesters (first - weeks 1-12, second - weeks 13-26, third - weeks 27-40). Without is an actual pregnancy confirmed by ultrasound, there are many milestones to pregnancy including audible heartbeat around 6 weeks of pregnancy, and feeling movement of the baby around 16-20 weeks.

Due dates are estimates, most babies are not born on the estimated due date, and only 5% of babies are born on the exact due date. It's a good idea to ask your doctor for expectorant tracking during your pregnancy.

Useful Tips 💡

Confirm your results with a "dating ultrasound" between weeks 8 and 12 for the highest accuracy.
If you have irregular cycles, the Conception Date method is often more reliable.

📋Steps to Calculate

Enter the first day of your last menstrual period (LMP).
Adjust for your average cycle length if it is not 28 days.
Click "Calculate" to view your due date and trimester breakdown.

Mistakes to Avoid ⚠️

Counting pregnancy as exactly 9 months; it is actually 40 weeks (roughly 9 months and 1 week).
Using the date of intercourse as the "Conception Date"-conception can occur up to 5 days after intercourse.
Not adjusting the calculation for cycles that are significantly shorter or longer than 28 days.

Practical Applications📊

Track due date for pregnancy planning.
Use with our BMI Calculator to monitor weight gain.
Plan prenatal appointments based on weekly milestones.

Questions and Answers

What is a pregnancy calculator?

A pregnancy estimator computes your delivery date based on your last menstrual period (LMP) or conception date. Our free online estimator provides an estimated delivery date and timeframe for your childbearing.

How to calculate due date from LMP?

To estimate your due date from an LMP, simply add 280 days to the first day of your last period. Our estimator will provide you with accurate, quick results.

Why use a conception date estimator?

f you're certain when you conceived, then the Date of conception estimator will help you know your due date more closely. Our online estimator uses the conception date to more accurately estimate your due date.

What is Naegele's rule?

Naegele's rule is the clinical standard for estimating the Estimated Due Date (EDD). It assumes a 28-day cycle and calculates: $\text{EDD} = \text{LMP} + 7\text{ days} - 3\text{ months} + 1\text{ year}$. Our tool automates this, including adjustments for varying cycle lengths.

What formula does the pregnancy calculator use?

Our tool uses Naegele's rule: due date = LMP + 280 days. The 280-day or 40-week standard is widely used by obstetricians in the medical community to track pregnancy.

How accurate is the due date calculator?

The due date estimator is an approximation of your due date. Babies will deliver when they are ready, and not necessarily on the approximate date provided, so use the due date as a guide, but lay your trust in the confirmation of medical professionals when tracking your pregnancy.

Can I use the estimator for IVF pregnancies?

For IVF, yes, you will need to adjust the embryo transfer date for how old the embryo was at transfer. Our tool can estimate your due date based on the conception date for any assisted pregnancy.

Disclaimer: This calculator is designed to provide helpful estimates for informational purposes. While we strive for accuracy, financial (or medical) results can vary based on local laws and individual circumstances. We recommend consulting with a professional advisor for critical decisions.