Baby Due Date Calculator – Estimate Your EDD From LMP, Conception or IVF
Baby Due Date Calculator
Calculate your estimated due date (EDD) using your last period, conception date, or IVF transfer details. Get your baby's expected zodiac sign!
Quick answer
A baby due date calculator estimates when your baby is likely to arrive. Choose your method (first day of last period, exact conception date or IVF transfer date), enter the date and your cycle length or embryo type, and click Calculate Due Date. You get your estimated due date (EDD), how many weeks pregnant you are, a countdown in days and your baby’s expected zodiac sign.
Our free baby due date calculator supports three methods in one tool, including 3-day and 5-day IVF embryo transfers, which many simple calculators leave out. Everything runs in your browser and nothing is saved.
Every due date is an estimate. A full-term pregnancy can last anywhere from 37 to 42 weeks, and only around 4 to 5% of babies are born on their due date. Your doctor or midwife may adjust your date after an ultrasound scan, and their date should take priority.
How the Baby Due Date Calculator Works
| Method | Formula |
|---|---|
| Last menstrual period (LMP) | LMP + 280 days, adjusted for cycle length (cycle length − 28 days) |
| Conception date | Conception date + 266 days |
| IVF, 3-day embryo transfer | Transfer date + 263 days |
| IVF, 5-day embryo transfer | Transfer date + 261 days |
Example: with a last period on 15 August 2026 and a 28-day cycle, the estimated due date is 22 May 2027. With a 5-day embryo transfer on 1 September 2026, the due date is 20 May 2027.
How to Use the Baby Due Date Calculator
Here is how to use the baby due date calculator.
Step 1: Choose Last Period, Conception or IVF
Open Calculation Method and select First Day of Last Period (LMP), Exact Conception Date or IVF Transfer Date.
Step 2: Enter the Date and Your Cycle Length
Pick the date in the calendar. For the LMP method, choose your average cycle length; keep 28 days if you are not sure.
Step 3: See Your Due Date, Countdown and Zodiac Sign
Click Calculate Due Date to see the estimated due date, how many weeks and days pregnant you are, days left until your baby arrives and the zodiac sign for that date.
Step 4: Using IVF? Pick a 3-Day or 5-Day Transfer
Choose IVF Transfer Date, enter the transfer date and select a 3-day or 5-day embryo transfer. The calculator adjusts for the embryo’s age automatically.
Which Method Is Most Accurate?
- IVF transfer date is the most precise, because the embryo’s age and transfer day are known exactly.
- Conception date is accurate if you know exactly when ovulation and conception happened.
- Last period is the most common method and works well for regular cycles; an early ultrasound may refine it.
Important Pregnancy Milestones
| Week | Milestone |
|---|---|
| Weeks 8 to 14 | Dating scan in many countries |
| Week 13 | End of the first trimester |
| Weeks 18 to 22 | Anatomy scan |
| Week 28 | Start of the third trimester |
| Week 37 | Baby is considered early term |
| Week 40 | Estimated due date |
Why Use a Baby Due Date Calculator?
Knowing your due date helps you plan antenatal appointments, maternity leave and preparations at home. A baby due date calculator also gives a simple countdown that many parents enjoy sharing with family. Remember that it is a guide; babies arrive when they are ready.
Frequently Asked Questions
Is this baby due date calculator free?
Yes. It is free, private and needs no sign-up.
How is a due date calculated from my last period?
The calculator adds 280 days (40 weeks) to the first day of your last period and adjusts for cycles longer or shorter than 28 days.
How do I calculate my due date after IVF?
Add 261 days to a 5-day embryo transfer date or 263 days to a 3-day transfer date. Choose IVF Transfer Date in the calculator to do this automatically.
How accurate is my due date?
It is an estimate. Most babies are born between 37 and 42 weeks, and only about 4 to 5% arrive on the due date.
Why does my scan give a different due date?
Ultrasound measurements in early pregnancy can be more accurate than period dates, especially with irregular cycles.
Is the zodiac sign accurate?
It is based on the estimated due date, so it may change if your baby arrives earlier or later.