Free Pregnancy Due Date Calculator
Find your baby’s due date by last period, conception date, IVF transfer, or ultrasound.
When is your baby due? Use this pregnancy calculator to find your due date based on the date of your last menstrual period, conception date, IVF three-day or five-day transfer date, or date of your last ultrasound.
Fetal Development 👶
This calculator provides estimated dates only. Always consult your healthcare provider for accurate pregnancy dating and medical advice.
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How Many Weeks Pregnant Am I?
To find how many weeks pregnant you are, count from the first day of your last menstrual period (LMP) to today.
For example, if your last period started 10 weeks ago, you are 10 weeks pregnant.
Use the calculator above — it automatically shows your current week of pregnancy along with your due date.
Here is a quick reference:
| If LMP Was… | You Are Approximately… |
|---|---|
| 4 weeks ago | 4 weeks pregnant (1st trimester) |
| 8 weeks ago | 8 weeks pregnant (1st trimester) |
| 12 weeks ago | 12 weeks pregnant (end of 1st trimester) |
| 16 weeks ago | 16 weeks pregnant (2nd trimester) |
| 20 weeks ago | 20 weeks pregnant (halfway) |
| 28 weeks ago | 28 weeks pregnant (3rd trimester) |
| 36 weeks ago | 36 weeks pregnant (near full term) |
Full term is considered 39–40 weeks. Babies born between 37–42 weeks are considered term pregnancies.
What is an Estimated Due Date (EDD)?
An estimated due date (EDD) is the date when your baby is expected to be born. It is usually 40 weeks (280 days) from the first day of your last menstrual period. Only about 5% of babies are born on their exact due date, but most arrive within a two-week window on either side.
How is Due Date Calculated?
This is the most common method used by doctors in India and worldwide. If your cycle is longer or shorter than 28 days, this calculator automatically adjusts the due date.
1. From the Last Menstrual Period (LMP)
The most common method is Naegele’s rule:
- Take the first day of your last menstrual period
- Add 1 year
- Subtract 3 months
- Add 7 days
This assumes a 28-day cycle. Adjustments may be made for shorter or longer cycles.
2. From Conception Date
If you know the exact conception date, add 266 days (38 weeks). This can be more accurate, especially if you were tracking ovulation or used assisted reproduction.
3. For IVF Pregnancies
Because embryo transfer dates are exact, IVF due dates are calculated as:
- 3-day transfer → add 263 days
- 5-day transfer → add 261 days
4. Using Ultrasound Scans
Ultrasounds (especially in the first trimester) can estimate gestational age by measuring crown-rump length or other growth markers. If ultrasound results differ significantly from LMP dates, doctors may adjust your due date.
Can My Due Date Change?
Yes. Your provider may revise it if:
- You have irregular cycles
- The LMP date is uncertain
- Early ultrasound results differ significantly
- Multiple pregnancies are discovered
Once confirmed by an early ultrasound, due dates usually remain unchanged.
Can I Plan My Due Date?
It’s possible to plan the season of birth by timing conception, but exact dates are unpredictable. Ovulation timing, sperm survival, implantation, and natural variation in pregnancy all play a role. The only way to guarantee a specific date is through a medically scheduled induction or cesarean section.
What Happens in Each Trimester?
First Trimester (Weeks 1–12)
The first trimester runs from week 1 to week 12 — the most critical period for fetal development.
- Major organs and systems form
- Heart begins beating around week 6
- Morning sickness, fatigue, mood swings common
Second Trimester (Weeks 13–26)
The second trimester (weeks 13–26) is often called the “honeymoon period” of pregnancy — symptoms ease and energy returns.
- Baby’s movements (“quickening”) felt
- Gender may be visible on ultrasound
- Energy levels often improve
Third Trimester (Weeks 27–40)
The third trimester (weeks 27–40) is the final stretch. Most hospitals in India schedule delivery between weeks 38–40.
- Baby gains weight rapidly
- Brain and lung development continue
- Baby usually moves head-down
- Mother may feel more discomfort, Braxton Hicks, sleep issues
Key Pregnancy Milestones by Week
| Week | Milestone |
|---|---|
| Week 6 | Heartbeat detectable on ultrasound |
| Week 8 | All major organs forming |
| Week 12 | End of first trimester — miscarriage risk drops |
| Week 16 | Baby’s gender may be visible |
| Week 20 | Anatomy scan (anomaly scan) recommended |
| Week 24 | Baby reaches viability milestone |
| Week 28 | Third trimester begins |
| Week 32 | Baby’s lungs developing rapidly |
| Week 36 | Considered late preterm |
| Week 40 | Full term — estimated due date |
Your doctor may schedule specific tests and scans at these key weeks. Use your due date to plan ahead for each milestone.
How You Can Use This Information
- Track pregnancy milestones
- Schedule prenatal checkups and tests
- Prepare for your baby’s arrival with more confidence