Knowing your pregnancy due date is one of the most exciting moments for every parent-to-be. This calculator helps you estimate when your baby may arrive using medically accepted methods such as Naegele’s Rule, ultrasound dating, and gestational age calculations used by healthcare professionals worldwide.
Whether you know the date of your Last Menstrual Period (LMP) or your ultrasound scan, this tool gives you a reliable estimation of your Expected Delivery Date (EDD) along with trimester details and important pregnancy milestones.
Our calculator uses the same formula your doctor applies during prenatal visits.
If your menstrual cycle is regular (≈28 days), your due date is calculated as:
LMP + 280 days (40 weeks)
This formula is known as Naegele’s Rule and provides a standard estimated due date.
Ultrasound in the first trimester is considered the most accurate method because fetal growth in early pregnancy is predictable.
If your LMP is uncertain or cycles are irregular, doctors rely on measurements such as:
If you conceived through IVF or know your ovulation day, your due date is calculated from the:
Conception Date + 38 weeks = Due Date
The calculator automatically adjusts for all of these methods to provide the most accurate EDD possible.
A due date is not an appointment — it’s an estimate. Only 4–5% of babies are born on the exact due date, but nearly all babies arrive within a two-week window on either side.
Doctors use the due date to:
Even though the due date is an estimate, it’s extremely helpful for monitoring a healthy pregnancy.
Pregnancy is divided into three trimesters, each with unique developments.
This is the foundation stage where your baby’s major organs begin forming.
Key developments:
Common symptoms:
This is also when your doctor schedules your first ultrasound, blood tests, and general health screening.
Often called the “golden trimester,” as most women feel more energetic.
Key developments:
Your belly becomes more prominent, and prenatal visits may include additional blood tests and growth monitoring.
Your baby gains the most weight in this trimester, and development prepares for birth.
Key developments:
Your doctor might recommend:
To better understand how a due date calculator helps, here is a real-style scenario:
Anna, a 29-year-old teacher, had irregular menstrual cycles. In early March, she felt unusually tired and noticed mild nausea. She took a pregnancy test which turned positive, but she wasn’t sure about the exact date of her last period.
Worried about tracking her pregnancy correctly, she visited her doctor. The doctor performed a first-trimester ultrasound, which measured her baby’s CRL and estimated her gestational age at 8 weeks and 4 days.
Anna then used an online Due Date Calculator, entered the ultrasound details, and instantly saw:
This helped Anna stay prepared for her appointments and understand her baby's development week by week.
Later, during her 20-week anatomy scan, the due date was confirmed to be accurate. Anna continued using the calculator to track her pregnancy until she delivered a healthy baby boy — just three days before her estimated due date.
This real-life example shows how a simple calculator provides clarity, reassurance, and accurate tracking even for mothers with irregular cycles.
Your doctor may adjust your due date because of:
The first ultrasound in early pregnancy is usually the most accurate, and doctors may rely on it more than LMP.
While this tool helps you estimate the timeline, your healthcare provider will guide you through essential prenatal checkups such as:
These ensure your baby’s health is monitored closely at every step.
These general guidelines help support a healthy pregnancy journey.
| Weeks | What usually happens |
|---|---|
| 6–9 | First scan / confirmation, heartbeat |
| 11–14 | NT scan + early screening |
| 18–22 | Anatomy scan (detailed ultrasound) |
| 24–28 | Glucose screening |
| 32–36 | Growth scans (if needed) |
Exact schedule depends on your doctor and pregnancy risk factors.
Most providers confirm or adjust EDD using early ultrasound if the difference is significant.
Enter your last period, conception date, ultrasound dating, or IVF transfer date and get:
Note: Only ~4–5% of babies arrive on the exact due date. Your baby is most likely to arrive within a 2-week window.
1) LMP Method: Last period + 280 days (adjusted for cycle length).
2) Conception Date: Conception/ovulation + 266 days (38 weeks).
3) Ultrasound Dating: Ultrasound date + (280 − gestational age at scan).
4) IVF Transfer: Transfer date + (266 − embryo age).
Tip: If cycles are irregular or LMP is uncertain, first-trimester ultrasound dating is usually the most reliable.
A due date calculator gives a reliable estimate based on standard medical formulas. However, only about 4–5% of babies are born on the exact calculated date.
Yes. Doctors may adjust your due date based on early ultrasound results or if fetal growth suggests different timing.
You can use ultrasound-based dating or conception-date calculation. Ultrasound in the first trimester is highly accurate.
Not at all. Ultrasound measurements help determine gestational age even when menstrual cycles are unpredictable.
Because fetal growth is very predictable early in pregnancy. After the first trimester, babies grow at different speeds.
Yes. Add 38 weeks to your ovulation or conception date for an accurate estimate.
This calculator is for educational and informational purposes only. It does not replace medical advice, diagnosis, or prenatal care. Always consult your doctor or healthcare provider for personalized guidance regarding pregnancy, tests, and delivery planning.
The due date is an estimation of when a pregnant woman will deliver her baby, typically 40 weeks from the last menstrual period.
Note: Results are estimations based on averages for single pregnancies.