Estimate Your Pregnancy Due Date Using Standard Medical Methods
Calculate your Estimated Due Date (EDD) using the Last Menstrual Period (LMP) or Conception Date method.
Pregnancy is an exciting journey that typically lasts around 40 weeks, but determining the exact due date can feel confusing. This Due Date Calculator helps you estimate your Estimated Due Date (EDD) using the same standardized methods healthcare professionals use worldwide.
Whether you know the first day of your last menstrual period (LMP) or your date of conception, this tool provides a clear, easy-to-understand estimate of when your baby may arrive.
This calculator is designed for educational and informational purposes only and does not replace professional medical care.
Calculation Method
Your Due Date
What Is a Pregnancy Due Date?
A due date is an estimated date when childbirth is expected to occur. It is not a guaranteed delivery date.
Only about 5% of babies are born on their exact due date. Most deliveries happen within a window spanning two weeks before and after the estimated date.
How Doctors Calculate Due Dates
Healthcare providers use standardized obstetric methods based on decades of clinical data. The two most common approaches are:
1. Last Menstrual Period (LMP) Method
This is the most widely used method. Pregnancy length is assumed to be 280 days (40 weeks). Counting starts from the first day of your last menstrual period, not conception.
Best for: Works best if your cycles are regular and you know the exact date of your last period.
2. Conception Date Method
If you know the approximate date of conception, the calculation becomes more direct.
Best for: Used when conception occurred via fertility treatments or ovulation timing is known.
How to Use This Due Date Calculator
Using this calculator is simple and requires no registration.
Step 1: Choose a Calculation Method
Select either 'Last Period' or 'Conception Date'.
Step 2: Enter the Relevant Date
Input the correct calendar date in the provided field.
Step 3: Calculate
Click 'Calculate Due Date' to instantly see your estimated delivery date.
What Your Result Means
Your result shows your Estimated Due Date (EDD).
- Is an estimate, not a promise
- Helps guide prenatal care milestones
- Is used to track pregnancy progress
Doctors often adjust the due date slightly after early ultrasound measurements.
Understanding Pregnancy Length
Pregnancy is typically divided into three trimesters:
First Trimester (Weeks 1–12)
Early development of organs. Often includes nausea and fatigue.
Second Trimester (Weeks 13–26)
Rapid fetal growth. Often considered the most comfortable phase.
Third Trimester (Weeks 27–40)
Continued growth and weight gain. Preparation for delivery.
Your due date marks the end of the third trimester, not a deadline.
Why Due Dates Can Change
Your estimated due date may be adjusted due to:
- Early ultrasound measurements
- Irregular menstrual cycles
- Differences in ovulation timing
Ultrasounds performed in the first trimester are often the most accurate for dating pregnancy.
Is the Due Date Exact?
No. Due dates are estimates.
The due date helps guide care, not predict exact delivery timing.
Global Medical Standard
The calculations used by this tool are:
Common Myths About Due Dates
"“Babies are born on their due date”"
Most are not.
"“Going past the due date is dangerous”"
Not necessarily. Many healthy pregnancies go beyond 40 weeks under medical supervision.
"“Due date determines baby’s health”"
It does not. It is a planning tool, not a health diagnosis.
Who Should Use This Calculator?
It is not a diagnostic or medical tool.
Pregnancy Milestones & Fetal Development
A week-by-week guide to your baby's growth and developmental milestones.
| Week | Milestone | Fetal Size (Approx) |
|---|---|---|
| Week 4 | Implantation complete; baby is an embryo | Poppy seed |
| Week 6 | Neural tube closes; heartbeat starts | Sweet pea |
| Week 8 | Major organs and tiny limbs forming | Raspberry |
| Week 10 | Embryo becomes a fetus; tail disappears | Prune |
| Week 12 | Reflexes develop; kidneys start working | Lime |
| Week 14 | Fingerprints form; can squint and frown | Lemon |
| Week 16 | Nervous system starts to function | Avocado |
| Week 18 | Baby can hear and may start to kick | Sweet potato |
| Week 20 | Halfway point; gender reveal possible | Banana |
| Week 22 | Sense of taste develops; hair grows | Papaya |
| Week 24 | Lungs start to develop surfactant | Corn |
| Week 26 | Eyes begin to open and blink | Scallion |
| Week 28 | Fetus can dream; brain very active | Eggplant |
| Week 30 | Early bone marrow produces red cells | Cabbage |
| Week 32 | Practicing breathing and swallowing | Squash |
| Week 34 | Central nervous system maturing | Cantaloupe |
| Week 36 | Baby shifts down into the pelvis | Romaine lettuce |
| Week 38 | Organs ready to function on their own | Leek |
| Week 39 | Full Term - optimal for delivery | Watermelon |
| Week 40 | Due Date - ready for birth | Pumpkin |
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Frequently Asked Questions (FAQ)
How accurate is this due date calculator?
It provides a medically accepted estimate, but actual delivery dates vary.
Can my due date change later?
Yes. Doctors may revise it based on ultrasound findings.
Is the LMP method accurate?
It is widely used and effective, especially for regular cycles.
What if I don’t know my last period?
Use the conception date method or consult a healthcare provider.
Is pregnancy exactly 40 weeks?
40 weeks is an average. Normal pregnancies range from 37–42 weeks.
Does ovulation timing matter?
Yes. Ovulation timing affects conception and due date accuracy.
Can stress change my due date?
Stress does not change gestational length but may affect symptoms.
Is this calculator suitable worldwide?
Yes. The methods are globally accepted.
Does this tool store my data?
No. All calculations run locally in your browser.
Can this replace doctor visits?
No. It is informational only.
Are due dates used to schedule inductions?
Sometimes, but decisions depend on medical evaluation.
Is delivering before the due date bad?
Not necessarily. Many healthy babies are born early.
Is delivering after the due date dangerous?
Not always. Doctors monitor overdue pregnancies carefully.
Does ultrasound give a better due date?
Early ultrasounds can improve accuracy.
Can twins or multiples affect due date?
Yes. Multiple pregnancies often deliver earlier.
Does this calculator diagnose pregnancy?
No. It assumes pregnancy has already been confirmed.
Limitations of This Calculator
- Does not account for ultrasound adjustments
- Assumes average pregnancy length
- Does not replace professional prenatal care
Always consult a qualified healthcare provider for medical decisions.
Educational & Medical Disclaimer
This Due Date Calculator is provided for educational and informational purposes only. It does not constitute medical advice, diagnosis, or treatment.
We are not medical professionals. Pregnancy care should always be guided by a qualified healthcare provider.